TOPIC: 1972? Evinrude 65hp Triumph: No power Underload?

65HP Electric shift. I've put in all, new coils, plugs etc.. Runs fine at idle. Warms up and gets up on plane nicely...for awhile Then slowly starts to loose power and then will die. Starts right up, goes into gear, no power just sort of idles along fine, (as if running only on 1 cylinder), but if I give it gas it stalls out. Some times it will go like this for 10-15minutes then it wants to get up and go again as if nothing happened. Did it again 1st time out last week. My thinking is that it is a coil issue,( intermittent spark to one or more cylinder,but they are brand new?).
Anyone who knows these motors need some advice.

You did not mention how long the engine has been sitting up or what work has been done to it so far to rectify the issue so give us a bit of history so that we can give better information back to you.
This sounds more like a fuel issue so lets start with the simple things first.
If it gets up on plane and runs for a couple minutes give or take and starts to lose power then do yourself a favor and take a fuel sample in a glass jar and check for water. Would take about that long for water to travel from a fuel tank through the fuel line and get to the carbs.
If no water.....While operating at the RPM/load the issue occurs at have someone pump the primer bulb. This will by-pass the fuel pump and supply the carbs with fuel. If it runs then you have a tank/fuel line/fuel pump issue to troubleshoot.
This engine has an early version of the later CD ignition with a timer base, stator with power coil and 3 ignition coils. Spark can be tested when the engine is exhibiting the issue to tell what cylinder or cylinders are not firing.

I bought the boat in Oct 17' and with winter setting in I only used it once and never noticed a problem. Summer of 18' used it often that's when I first noticed it would regularly behave this way. Pumping the fuel doesn't help. It had cracks on all the coils (figured that was the problem,but winterized it and and let it sit till Summer of 19' when I replaced all the coils,plugs and wires it still did it and once again I just lived w/it and then stored it for the winter. Come Summer of 2020/Covid we never used the boat until a couple of weeks ago, she started right up and I put a timing light on at idle and all cylinders were firing At Idle but NO Load. We took it out still same trouble. Can't tell if replacing the coils did any good.
Never checked to see if H2o is present, I'll do that to make sure thanks for the tip.
Question?
If h2o is/was present, why does it run on only one cylinder and only do this intermittently, then clear up after awhile?
I'll try to run it under load at dock with timing light to see if under load, the coils/plugs are still functioning.
Thanks for your prompt response.

Follow the fuel lines from the pump to the 3 carbs & you will see where they "T" off. Water being heavier will typically fall to the bottom carb.
If you have water, then when it is misfiring you aren't getting oil either. If you have dirt in a carb, again when fuel is plugged, so is the oil.

I realize the plugs are on the far back & you are typically using it in the sun, so it's hard to reach/see if you have spark but you could also have a failing CDI or trigger or a bad wire. FYI, OMC triggers are very reliable.
An inductive timing light could be used to see if you have spark on each cylinder without having to pull plug wires & could be installed when problem develops on the lake instead of at the dock.

That engine has the plastic plugs in the front of the airbox we can use to establish whether or not it is fuel or ignition.....after you establish the presence of water or not.
One thing at a time though so report what you find.

Thanks Guys:
I'm busy till Wednesday this week but I'll check it than and respond.
Thanks for your input and encouragement.
Gene

Took boat out again yesterday. Like clockwork at about 1/4 mile motor slowly lost power, pumping fuel bulb did Not help made it die.
Starts right up again and limps along at idle, give it more throttle and it dies.
Fuel is good, new coils,plugs and wires. Cleaned carbs, fuel pump works.
Must be simple since it runs full power fine for a short time.Never did this when we first bought boat 4years ago?
What am I not seeing here.

Okay, one of your comments may be a key to it. When you pumped the bulb and it died. That may indicate a leak in the diaphragm on the pump. I believe that pump is a 3 line pump. If so remove the pump and the air line or at least just the air line.
Once removed pump the bulb on the Boat's fuel line with the line still connected to the engine. If fuel comes out of the air line on the pump you will either need a new pump or a kit to rebuild that one. The diaphragm will be leaking.
Lets start with this check.

Thanks, Pappy:
I'll try that ASAP and let you know.
I appreciate your response

Hi Pappy:
I tested the fuel pump like you said, No fuel coming out of airline. I ran motor at idle on ear muffs for well over 15 min. never skipped a beat. Than ran it at idle in gear,slow rpm, never skipped a beat. All cylinders are firing(timing light). Also checked head temps on all cylinders (all reading about 135-138 degrees F.).
So I'll try to take it out on water this weekend. God willing, she'll run right, or at least give me something definitive to help diagnose the real problem?
Thanks for your input.
Del

Dumb suggestion maybe too late but is your tank breather open? Loosen the cap on the tank while you're running. If you have an inboard tank make sure no mud wasp plugged things up.

Hey new guy here, I have the same exact motor and having the same issues as stated above. just curious as to your findings as to why it won't go under load, mine revs fine in neutral but not in gear usually stalls out as I put in gear. sometimes wil go Into gear and idle but no throttle. been trying to find a way around this issue for a few months. about to buy a new motor..

I had one of those motors a while ago . Same problem no power under load. I found that it burnt a hole through a plate that separates water from exhaust , I found a new piece and replaced it and regained power. I noticed paint was burnt of the side of motor where exhaust runs down to lower unit. Three mechanics looked it over and could not solve problem . So I took a shot and that was what I found

Thanks all for the input.
I just got back from the lake where i ran boat on trailer. Same problem at the start.....until started to fiddle with the low idle screws and surprise, surprise, I got to to run full throttle,at full power:woohoo: Don't know why low speed idle screw adjustment would affect the high speed running but it did. I never rebuilt the carbs so I'm going to do that and test it again. So now I/we Know it's a fuel issue, maybe more who knows.
BTW
Hodgify, I'm going to look for burnt paint on the lower unit, that could be a"masked problem"
Like keep you all informed. At least now I have something to go on.

Good for you! Yes you need to get in there and clean the carbs. Purchase only OEM kits. They are the only complete kit on the market. The rest do not have floats and other parts in them.
Now, The reason the idle mixture affects the acceleration onto plane is that both the idle or low speed mixture and the high speed circuit overlap each other for a small percentage of time or throttle angle. For this reason the idle mixture has to be rich enough to contribute to the acceleration phase long enough for the high speed ciircuit to take over and support the engine.
Sorry I did not see your post until now.

know what plate exactly ? not sure where too look I have a feeling this mightt be my case.. cleaned carbs 3 times, all new fuel , and tank and line.

delvel wrote: Thanks all for the input.
I just got back from the lake where i ran boat on trailer. Same problem at the start.....until started to fiddle with the low idle screws and surprise, surprise, I got to to run full throttle,at full power:woohoo: Don't know why low speed idle screw adjustment would affect the high speed running but it did. I never rebuilt the carbs so I'm going to do that and test it again. So now I/we Know it's a fuel issue, maybe more who knows.
BTW
Hodgify, I'm going to look for burnt paint on the lower unit, that could be a"masked problem"
Like keep you all informed. At least now I have something to go on.

It's a system, so if the low-speed circuit is too lean, you'll have acceleration problems and the engine will be very cranky.

I'm assuming yours still has the airbox cover installed, and the tie-bars between the idle mixture screws.

What you want to do now is make sure the idle mixture screws are synchronized. So take the boat out, get the engine good and warm, then pull the airbox cover and pull the interconnecting idle mixture linkage. Then you can adjust each idle mixture screw separately, with the engine idling in Fwd gear.

Start at the top; very slowly screw in the mixture screw (clockwise=leaner) until the engine starts to cough/stutter. This is the extreme lean setting. Then back out the screw until that carb goes rich and the engine slows down a bit. That's your extreme rich setting. What you want is somewhere in-between those two adjustments. Such that the engine runs smoothly and idles cleanly, at its best speed.

When you find that point, turn the mixture screw about 1/8-turn CCW (rich) and move on to the next carb. These engines have no accelerator pump, so you have to set the mixture a bit on the rich side for good acceleration from idle.

Once you have all 3 mixture needles adjusted, reinstall the airbox cover with a couple of screws and test your hole shot. If it accelerates cleanly from a dead idle, you're good. If you get a bog or hesitation, turn each idle screw another 1/8-turn CCW. That should do it.

Once the mixture screws are all adjusted properly, reinstall the tie-bar linkages, with the adjustment range set to about 1/2. That way you'll have adjustment in either direction, as needed.

HTH & let us know how it goes............ed

The Saga Continues:
Last week did static test with boat in water on trailer. AS usual engine started right up idled well and warmed up engine and ran it in gear while adjusting all carbs(did not disconnect linkages). Got engine to run really good at full power. Figured problem was solved?
Yesterday, did the same(ran boat on trailer). 1st off... Engine would not start right up? Took forever,flooded out( never does this at all) had to change plugs to finally get it started.WHY??
Finally got it warmed up and followed ed-mc's instructions; disconnected choke and throttle linkages, adjusting each carb in sequence..Reconnected linkages. Engine now runs rougher and never quite reaches peak power out at high end without breaking up(ends rough, now and is hard starting).
What did I do wrong/ Carbs out of sync? I'll try again this weekend.

P.S.
The dock fishermen are getting tired of me making noise & prop wash, If this keeps up I'll have to change docks.

Hi Ed:
I'm gonna rebuild the carbs this week.
Question: ON the needle settings( screws) once carbs are rebuilt how many turns out do I make initial settings? 2-1/2 for starters?
FYI : using your instructions I got it running really good under full load last week but then it would not idle or start easily.
Good news is she really wants to run:cheer:

1 1/2 is a good place to start and lean them from there.

Based on much experience, I say that motor is ingesting water into the cylinders. They are notorious for that. It is a warped baffle plate in the exhaust covers.

Not meaning to be nasty, but the water usually destroys the powerhead bearings before anybody figures out what is wrong.

Interesting. Well if that's the case I'll run it till it implodes and use it for a dock anchor. Certainly not worth tearing into. I'm already searching for a replacement motor.

I would say lets go for the simple things first.
Typically when an engine has a leak at the inner exhaust plate the engine will start normally and run until the powerhead fills with water and water pressure then leaks past the warped part and into the cylinders. At that point you drop one or more cylinders and when you pull the plugs you will see water on them and or they will be sparking clean compared to cylinder (s) that are not leaking. That does not take long. You ran much longer than that. You changed plugs.....did they all look the same or close?
If your engine is flooding and you are sure of it do a fuel pump leak test. Remove the pulse line if so equipped and undo the pulse hose from the pump. Squeeze the primer bulb and if you see fuel leaking at the pulse line then your diaphragm in the pump is leaking. This will flood the engine regardless of needle settings. This is a quick check and we can cross it off the list.

Thanks, Pappy. Waiting for new Carb rebuild kit to come. we'll see in a few more days. The Kookenai are waiting1

I trust you are using only OEM kits? They are the only complete kits out there.