TOPIC: Fuel in Oil and low RPM with 1972 Bearcat

Hello Everybody.

I am Patrick from Switzerland and I am running a 1972 Bearcat 55 on a 1964 "Spiboot Taifun". Theses Boats are out of aluminum and were made in Switzerland, but this is the only forum I found which has a separate section for Bearcats, so I hope that is ok.

The Problem:
I was running at full throttle at about 5400 rpm for about 10-20 minutes in the lake. Suddenly rpm dropped to about 2000 at full throttle. I was not able to go over these 2000 rpm again. But the engine started and idled just fine. The problem seems to only exist when a gear is put in, in neutral the engine seemed to rev up fine.

I took the boat out yesterday and I realized there is a severe amount of fuel in the engine oil, I would say almost close to a gallon (!) and the level was accordingly high!

The first thought was the diaphragm of the fuel pump (the original one) and this suspicion was also confirmed by Bill. So I unmounted the pump today and tested with water. But it builds up pressure nicely and holds it for a while without a lot of water leaking out of the opening where it mounts to the engine.

I should get a new mechanical pump from Bill soon. But do you know of any other way how that much fuel could get into the engine?

It's possible that you didn't see a leak with the water if the pump wasn't running at engine rpm while testing.
All cases of fuel in oil I have personally seen have been due to failed pumps. There were two styles of pumps used, the first series had rebuild kits available, the second series were just remove/replace with no factory pump rebuild kit available.
I have mechanical fuel pumps available as emailed.

Yes Bill you are right. I am probably just not able to simulate the actual rpm to the pump by hand since I am not able to push it a couple thousand times per minute.

After pushing the pump about a hundred times while pumping water I took it apart again and there was definitely water on the wrong side of the diaphragm.

I sent you an eMail with the order for the new pump. Hope to hear from you soon, I really want to get the boat back into the water as soon as possible.

I will post back when further progress is made. Thank you!

EDIT:
I just saw a similar topic already exist: www.fiberglassics.com/fiberglassics-forums/home/homelite-bearcat-4-cycle-outboards/gas-in-oil

OK, so a new mechanical pump from Bill should be on its way to Switzerland soon. Thanks in advance!

Just to make sure everything is fine with the engine I decided to measure the pressure of each cylinder. If I got that right from here the minimum pressure should be no less than 130psi. I will post the results as soon as available.

One more question: Can anyone explain to me what the hose which ist attached to the intake-silencer is for and to where it is running (picture attached)? Anyone else running with the silencer?


EDIT:
So I did meassure the cylinder pressure yesterday. I am pretty happy with the outcome, what do you think? (Cylinders from top to down)
C1: 190 psi
C2: 190 psi
C3: 180 psi
C4: 190 psi

What are advantages / disadvantages in between a new mechanical and a new electrical fuel pump?

I'll just contnue to write to myself, maybe it helps someone in the future.

So I decided to go for a pump from the german manufacturer "Hardi" with a working pressure of 0.2 Bar (about 3 psi). I will post sometime in the future how this worked out.

Where I really need your knowledge and I'd really be grateful for a reply:

What is that weird hose for from which I posted a picture above for? I really have no clue and I have not seen it on any other pictures of bearcat engines.

pdomenig wrote:

Where I really need your knowledge and I'd really be grateful for a reply:

What is that weird hose for from which I posted a picture above for? I really have no clue and I have not seen it on any other pictures of bearcat engines.

The hose is the crankcase breather, it should run up through the white plastic loop on the oil pan then back down to the hood pan, through a hole by the "V".

The electric fuel pump requires mounting and wiring whereas the mech bolts in.
Many guys complain about elec fuel pump noise.

In either case you should use an inline filter and ditch the old glass strainer bowl.

I am running one of my mech pumps on mine, took it out for a 5 or so mile run in chop last night and she didn't miss a beat. If she had, it would not have been a good night.

Re the breather hose Dick is spot on. That hose needs to be looped up through the white hose clamp and passed down to the hole near center of the V on the lower pan.
Will post a pic. Make sure the hose is clear, blow through it to check. It vents the crankcase via the oil sump to atmosphere and prevents oil puking out via the long run up to the clamp (gravity at work.

Thank you so much, I really do appeciate your help!

I think I now understood all parts of the engine (in general) and I hope to get it back in the water this weekend. I will let you know as soon as there is any progress.

I wonder who had the idea of connecting th crankcase breather to the intake silencer.

New fuel pump (Hardi 14412) is mounted:

I think I just found the real reason for the sudden power-drop I experienced while driving at full throttle. The problem with the fuel pump and the fuel in the engine propably wasnt the reason for this (but still it is a problem):


I had put some oil/fuel absorbing towels in the engine in order to prevent anything from going into the water. Looks like one of these towels has been sucked in through the intake silencer and fully closed the lower carburetor.

I put the boat back into the water and the bearcat is running nicer then ever before!

I can really recommend the fuel pump. It is self regulating, meaning it turns off when the pressure is high enough. So when the ignition is turned on it clicks about five times and then stops. While the engine is running one can not hear the pump.

Thank you all for your help and inputs! But I have two more questions:

1. I realized that the wire running from the junction block to the coil is getting slightly hot. Is this normal? Does this wire have any special properties or can it be replaced by any wire?

2. Did anybody from you experience changing idle rpm? My idle-screws don't seem to stay where they are supposed to be. So for example after running full speed for about 10 minutes the idle rpm ist at 1500, but it was set to 700. This can be readjusted with the idle screws, but it is enoying.

pdomenig,

WELCOME ABOARD. - We're glad you're here.
(I wonder how many nations that the forum has as members???)

yours, satx

This engine is starting to really annoying me, just about to sell it. Every single time I use it there is a new problem, even though I keep on investing hours and money.

Idle RPM varies greatly depending on engine temperature.

Battery charging does not always work.

Cooling no more working good at idle speeds, not enough water comming out and steam.

And here is my newest problem. Could anyone tell me what these openings are for? I was not able to find any information on that.



The did not happen while the engine was running. I just returned to the boat after a month of not using it and I saw this. I was thinking about freezing (even though we almost had no low temperatures), but there should be no water behind there, right?

Hi, that is a missing freeze / core plug and is in the water cooling jacket. Plug should still be in the bottom of cowl, may have frozen or just popped out. The large opening will dump all cooling water right there. Need to get it back in or get a new one if it wont stay in there.
Skip

Idle RPM varies greatly depending on engine temperature.
Did you adjust your throttle link rod such that when both throttles are closed the link rod closes both of them? Then, did you open the throttle equally for a idle rpm of 750 or so, then optimize idle speed by adjusting the mixture screws? This will help stabilize idle, but yes there is some idle speed difference at 0 degrees C versus 25 degrees C outside temperature.

Battery charging does not always work.
What is your voltage at idle, what is it at 2000 rpm? Could be a connection, could be rectifier, could be the magnets in the flywheel. You have the book, it's not that hard to troubleshoot. WOrst case you have to swap out the flywheel, I've only seen that twice over the years though.

Cooling no more working good at idle speeds, not enough water comming out and steam.
In my experience this is usually due to scale in the block cooling passages. However, if engine is on boat in water, and you warm it up do you have cooling flow at 1500rpm? At idle? If not at idle, shut down motor, pull the shift shaft rod inspection cover right side of upper leg. Restart engine, do you now have flow? If the flow increased it's a known problem where the factory fix was to drill 8 1/8" holes in that plate to allow exhaust pressure to be relieved in the leg. THe scale problem is the first thing anyone should tackle prior to running one of these on the water. You have to disconnect battery, they pull starter and remove the water jacket plate from left side of block. Once removed, do you have rust scale piled up inside the water jacket cavity?? If so, get a pick or little screwdriver and loosen it up. If you have a small wet/dry vacuum suck all the scale out. THere should be a passage under the number one bottom cylinder to the right side of block, that must be clear.
Check telltale hose for clear passage, is the restrictor installed in end of telltale hose. Descaling makes a HUGE difference, usually the single biggest improvement. I forgot to say, before you do all this if you only run the engine for say two minutes to test disconnect the water feed hose at the T left side of block and pull shift rod inspection plate. Start engine, water should be coming out of the hose strongly, proving you have water coming from the water pump.
I'm sure Dick will chime in and cover anything I've overlooked.
If the engine runs well, it's worth just doing a few more things to it to ensure it runs well. IF you get another engine you have to start over, unless you buy a new one for around $6K USD...........
SPucky is right about the freeze plug, 1 1/8".

You are dealing with a 43 yr old engine. Unless you've went totally through all maintenance procedures, to expect a turnkey operation is just not reality. Your over heating problem is due to the missing soft plug. How can that have come out, it hasn't been in freezing weather? Age, installed incorrectly previously, hard to find an exact reason. Can it happen, just fall out, unlikely but as you can see not impossible. Have you performed the maintenance to the cooling system Bill has described? What condition is the impeller in? Does the engine still have a thermostat? These are sometimes eliminated and will affect how the engine performs depending on water temps. As Bill mentioned it's possible for the flywheel magnets to become weak which will affect the charging. I too have one here that was weak. What's the output voltage of the stator? Could be weak magnets or the stator has gone bad. Have you tested the rectifier, done a compression check, valve adjustment, cleaned the carbs? Replaced cap, rotor, points and condenser or switched it to electronic ignition?

Bottom line is the local Bearcat dealer has been gone now for 43 yrs and maintenance of these engines is pretty much in the hands of the beholder. If you can't do it yourself you're pretty much screwed unless you know of and are willing to pay to have it done. When properly maintained they run like a sewing machine and will give many hrs of turnkey troublefree operation.

"Just ask a man who owns one." or two, or three.................

Thank you all for your very extended and detailed answers! I really do apreciate all the information you do provide! I wasn't around for a while since we had quite some winter during the last few month, so I went skiing no boating.

I am very well aware of the age of the egnine and the maintenance (or love as I call it). My mood just had a low after returning to the boat and finding all these problems. However, yesterday I went out on the boat again, so it is up and running again. Looking at prices for alternatives remotivated me in no time!


@spucky:
Thanks for the quick explenation of the "hole" or rather freeze plug in the engine. I have found the missing part just where you said it would be. I cleaned everything from oxidation. Then I reinserted the missing part with a simple hammer. On the first run this was no completly sealed and some water was leaking out. On the second run a few days later everything stayed dry. So I guess chalk or dirt sealed it again.


@billr:
Idle RPM
Throttle link rod adjusted? => Yes, they work in parallel and do fully close an open equally. I think the problem is that my mixture screw keep moving due to the vibration. The problem is not minor. I can set the idle rpm to 800, then go full throttle for 5 Minutes, this can (but will not always) result in an idle rpm of over 2000. Small changes have to be expected due to temperatures and so on, but I think this is a lot. Am I maybe using the wrong screws? Image attached.


Battery
Well, after testing for multiple hours I found the error. I tested the engine and this was charging quite strongly, so I searched for other causes. The battery-checker I have mounted on the boat was not disconnected by the main switch. I guess after such an extended period of time even such a small usage can kill a battery. So this was my error. Big sorry to the engine from me

Cooling
I have already mounted a new impeller and a new thermostat from you. Descaling was the solution, at least during the last two runs I had no problems at all and I always had water comming out, even at very low RPM's.

@4stroke:
Your over heating problem is due to the missing soft plug. => Did you mean the freeze plug? This happend after the overheating, but I hope this has been solved.
ow can that have come out, it hasn't been in freezing weather? => I guess not, but I don't know. We didn't have very low temperatures until this happend. But it is fixed now.
Have you performed the maintenance to the cooling system Bill has described? => Impeller and Thermostat were new before the problem appeared (supplied from Bill). Descaling seems to have been the solution.
Have you tested the rectifier? => No.
Done a compression check? => Yes, everything fine, posted above in this thread.
Valve Adjustment? No, but no suspect noices or reason to to this at all. Also this is about where the limit of my engine knowhow starts to appear.
Cleaned the Carbs? => Yes.
eplaced cap, rotor, points and condenser or switched it to electronic ignition? => No, but an electrical fuel pump.
These are sometimes eliminated and will affect how the engine performs depending on water temps. => Could you give more information about this? Do you guys don't have thermostates?

Well I have just realized that maybe I have been adjusting the idle rpm wrong. There are "idle stop screws" and "idle mixture screws".

So far I have always been using the stop screws. I guess that is wrong. Is the procedure how to adjust these screw outlines somewhere? Do you first adjust the mixture screws and then the stop screws?

My problem seem to be the stop scews which don't stays where the are supposed to stay.

A few questions concerning the coolling system.

Did I get this right, when the engine is cold the thermostate and therefore the bypass is fully open, so the complete water passes by throgh the thermostate and the exaust? When the engine is hot the thermostate closes and the water goes through the engine-block since the bypass is closed?

I read that some remove the thermostate completly. Wouldn't that mean that all the water goes through the engine block and nothing into the exhaust? Is this OK or does the exhaust have to be cooled?

This weekend I had some cooling problems again. Realy weird ones. Sometimes it worked fine, sometimes there was not water cumming up from the pump at all. But for which reason should the pump sometime pump and sometime not, independant of the rpm? The engine-block is clean, no blockage there.

yes, bypass open when cold so that the water in the block will heat faster. the f model retains the water in the block on shutdown, earlier models drained block on shutdown.
once block warms up the thermostat expands and closes bypass.
the exhaust must have water, and it does whether bypass providing it or block providing it. otherwise the elbow o ring would melt.
to bypass the thermostat, the water must exit the block through the upper opening under thermostat, and exit through the small opening. so the way to do it is put the thermostat cap on, plug the bypass hose nipple.
do you have relief holes in your shift plate? when was the water not coming up from the pump? how do you know you had cooling problems? did the overheat light come on?

I realized I had cooling problems before the warning light came on since no water but steam was comming from the telltale. But later the warning light turned on.

This weekend I went to the boat to do some further test since I am now sure I understood the cooling system. Thank you for your explenation!

So basically not all of the water which passes through the engine block leaves by the tell-tale, some of it goes through the exhaust. Right?

I took of the hoes which comes from the pump and closed the hose which goes to the thermostat with tongs just to shortly test if there was water cumming from the pump. Even at 2000 rpm there was almost no water cumming up from the pump (engine completly cold). I have a new blue impeller from billr installed. I am going to clean everything up and let you know if there were any improvement.

Which is the "shift plate"?

Edit:
If I remember that correctly I broke one of the screws from the pump-hounsing when I exchanged the impeller. But I thought 3 of the 4 screws would still be enough. Do you think that there could be such a severe leak due to this missing screw that the pump stopped pumping completly?

So basically not all of the water which passes through the engine block leaves by the tell-tale, some of it goes through the exhaust. Right?
VERY little water should exit the telltale with the restrictor pipe in the end of the telltale hose. When engine is off and cold, block is full of water, thermostat is fully open. Open means the bypass hose has no restriction, however the block is nearly fully sealed off from water flow from the block. The exception is the small relief hole in the thermostat diaphragm.
So again, upon starting the cold engine, since the thermostat is open to bypass, the running engine heats up the water in the block faster since there is no flow through the block other than through the telltale and the relief hole in the thermstat diaphragm. At the same time, the exhaust is cooled with full water pump output via the bypass hose.
BYPASS means you are bypassing the block, think of it that way.

As the engine warms up, the thermostat element begins to heat up and expand moving the valve (white disc that seals off flow) TOWARDS the bypass hose. At this point there is some flow from the block, and some from the bypass hose.

WHen the engine is fully warm under load, the bypass is blocked off, all water from the water pump goes through the block and out the exhaust, and a little out the telltale.
So the outputs for the water pump are through the bypass to the exhaust, and through block then the manifold then out of the telltale and into the exhaust.

In use, the thermostat is constantly going back and forth, and the key point is that the exhaust always has cooling water whether the block or the bypass hose have flow. Earlier models did not have this and burnt elbow o rings were a problem.

ALL of the above is dependent on Full water pump output. Meaning the pump can input and output water.

It sounds like you have no pump output. THe easiest way to see this is disconnect the bypass hose and feed hose to port side water jacket from the water pump output short hose on left side of engine. Start engine, full water flow should be coming out of the hose. IF not, pull lower unit. Pull water pump, see if the key is still driving impeller. Look inside the passage from pump to the inlet screen. I have seen old impeller parts blocking this, plastic bags plugging the screen, and other stuff like tools in there. You need to prove that the inlet to the pump is clear. Then is impeller/key correct, then all four screws need installed correctly. Is the liner installed correctly in the pump housing???
All of the above should be in your manual too so also refer to that.
Once you reinstall, start engine with the feed hose open and water flow should be excellent. THen reconnect hoses. If anymore troubleshoooting needs done it's block/manifold/thermostat. DId you clean out your block water jacket? I would do that too, nearly every engine hasn't had it done and it makes a HUGE difference.
OK, I'm done.

Thank you Bill for this extended answer! I will go through it step by step, boat will be taken out tomorrow. The block is clean, I seem to have a pump problem which is not persistent, sometimes cooling works, sometime it doesn't.

I was on the boat a few days ago to check everything again, but everything just worked fine and therfore it was not possible to analyse the fault. Since it worked I decided to go out, I made a short video out on the lake:


I will let you know when there is any progress.

I have not taken the boat out of the water yet, but I have checked the complete cooling system. Thanks for to you I now fully understand how it is working. All hoses clear, engine block clear, thermostat working. The problem is definitely coming from the pump.

I don't think it has anything to do with a blocked input or output, this would not result in working sometimes and sometimes not. Basically it seems like the impeller is sometime just not turning with the shaft, that is the only logic explanation. Also there have been reports that this happened with Globe-Marine impellers on other engines.

Are there any other impellers available or only the blue ones from Global Marine (Model 233)? There are numerous reports that this propeller results in week water flow and idle-overheating. The one I had in there originally was a black one but has nothing written on it.

The blue Globes are the only ones I know of, #223. I've used one of these with crap results. The driveshaft hole was not bored straight, rather at an angle. Wouldn't pump good so out it came and a used OEM went in it's place that works just fine.

My dad sold his Bearcat to a guy who had overheating problems, paid someone to replace the impeller with no improvement, and he ended up selling it back to me. I replaced the new impeller which had a couple deformed but intact blades. Closer inspection revealed old blade fragments down on the water intake screen that I assume were sucked up and had gotten stuck in between the blades and pump housing, deforming the impeller blades (problem one; solved by removing all the old blade fragments and installing a new impeller). Make sure there are no old impeller pieces down in the intake. Problem two was that the seal around the drive shaft in the top pump housing was bad and needed to be replaced. The spring around the seal lip had actually rusted and broken, and the rubber seal itself had deteriorated.

I'd just pull the lower unit and see what the impeller looks like. I'd also make sure the tube(s) between the lower unit and the motor are connected properly.

This is really hard, but the decision has been made: The engine is up for sale.

If there is anybody who would have interest in it, I am giving it away cheap. By the way, it is a shortshaft. Included will be 3 propellers, manual and service manual, a new thermostat, replacement and OEM Impeller, original mechanical fuel pump and electric fuel pump and the remote control (not original) as well as RPM gauge and ignition-key. At the moment the only problem it has are with the cooling at idle speed. As posted is has more then perfect compression on each cylinder.

I love this engine and it fitted absolutely perfect to the old boat. But I go boating to relax. During the last days on the boat I was not able to enjoy it anymore since I was always afraid if I'd be able to get home or not. I have invested a lot of money and time, but I just can't take this any longer, it's not what I am looking for while boating.

Thank you so much for all your help, you really tried hard, but it seems I just don't know enough about such old engines to keep it running reliably.

...I am almost crying I feel so bad about giving the engine up...