TOPIC: evinrude starflite fat 50 fuel problem

Latest problem with the 58 evinrude starflite fat 50.

I replaced the fuel pump diaphragm and made sure the short and small springs were installed correctly. And i rebuilt the carb.

Carb is #377121 and may be a newer model? The rebuild kits have packing nuts but this carb has o-rings.

Problem is, motor runs when i pour premix in the top of carbs but it stalls out after fuel is used. The bowl fills up when primer bulb is squeezed (the filter in bowl is new also). I was removing the fuel hose at rear of carbs and pressurized fuel sprayed so i'd imagine the fuel pump is pumping to the carbs.

What could the problem be? The carbs do not seem to want to take fuel. Yes i set the float level per Seloc and Clymer manuals.

This is the exact same problem i had before rebuild so i doubt i did something wrong.

One more thing. I am replacing the spark plugs and checking compression tomorrow but i don't think either is the concern since it runs good until the "primer" is used up.

How are the fuel lines on the motor? Are they cracked or hard? The new gas eats away at them from the inside and can cause small pieces which can plug a jet or bowl fill or big ones that can severly restrict your fuel flow. You could have cleaned the carb and just by pushing fuel through the lines clogged it right back up. I would check my jets again and make sure they aren't clogged up again. You are on the right path, it sounds like it's starving for fuel. If you pour it in it runs, then gas supply is the problem. I once cleaned my carbs 3 times on my motorcycle when it wouldn't run right third time was a charm, whatever it was I got it out. Use plenty of carb spray in every hole and clean the jet out good, and never give up.

Thanks Homebrew. I know for a fact i cleaned it good the first time!
Just kidding. When i tore carb apart again i found small chunks of what looks like hose. Hoses looked good and were pliable but obviously breaking down. I also noticed excessive crap in sediment bowl.

Tomorrow it will get all new fuel line and fuel pump will get cleaned out good.

If you have a motorcycle service shop in your area, go purchase motorcycle single wall fuel line. I like to use Honda fuel line, as it is very pliable. Any hose for motorcycles that has been made within the past few years will be alcohol rot resistant. The auto parts stores will only have double wall reinforced fuel hose or Marine hose. You don't want that - it's too heavy/thick. Don't use vacuum line, as it is not generally rated for fuel. I discovered motorcycle hose many years ago, and have used it ever since. It is just what that engine requires.

As for the carb, did you clean the main jets? You will want to remove the two drain plugs on the bottom front of the fuel float bowl. Then carefully run a wire through the main jet orfices. A strand of "telephone wire" with the insulation stripped off works great. You need a very thin wire. Bailing wire isn't likely to work. Push the wire in as far as it will go - be sure the wire enters the jet. You can remove the main jets with a modified 3/8 flat blade screwdriver. File/grind down the shoulders of the blade 'till it will JUST pass through the drain openings on the front of the carb. Do not force - be sure it fits. Be very careful removing the main jets. And yes - even though the fat 50 has adjustable meeting screws for the main jets - it DOES actually have fixed main jets inside those holes.

Hey Bruce great idea on the telephone wire. I have a friend that does acupuncture so I have a handful of those nice long needle thingys. They work great for cleaning main jets. And they come individually in nice little plastic tubes to store them away.

Found my problem.

Junk in sediment bowl.


I went to Honda cycle shop and got some of the fuel line that was recommended. When i removed old fuel lines this is what i found in them. Possible cocoon remains.

Nice work, nothing worse than a critters nest in the fuel line. Now get that thing running.

Probably from Leaf Cutter Bees. I'm forever amazed at where those little things lay eggs. Seemingly impossible places like fuel line, but somehow, they get into the wierdest places. They clip little sections off of leaves that are tender. They haul it off to a ready made place like a nail hole, Telltale hole on an outboard, fuel line. They make little capsules of the leaf parts & lay their eggs.

Bruce, Motorcycle line is a great tid bit of information. I've had a lot of rebuild projects where car fuel line is too fat and won't bend sharp enough. I never knew such an item existed. Thanks!

X2 on the motorcycle fuel line. Nice to work with.

Well, I cleaned Carb again, replaced all fuel lines, replaced plugs, etc.
Still having the same concern.

I took fuel pump apart and found a check valve lodged open. I popped the little disc back in place and tried running motor again. It ran far 15 seconds and died.

I got a fuel pump rebuild kit on the way.

Anyone have any other ideas? Could a long hose to the fuel tank be too much for the pump to handle? I'm also trying another Carb.

Again...runs when premix is poured in Carb but dies out and will not run without more premix.

Just for the sake of mentioning it - is the fuel hose plugged in with the arrow going toward the engine? You wouldn't believe how common of a mistake that is. If you "bulb" the fuel line does the carb bowl fill with fuel? If it does fill, then after the engine starts and dies, try unscrewing one of the float bowl drains on the carb. If no Gasoline drains out of the carb, then the fuel pump is not working, or there is a problem with the fuel system ahead of the pump. If gasoline does drain out of the carb - the the fuel is not getting past the carburator. Did you check the float for the correct setting?

Testing pic upload.
The check valve in fuel pump popped again. I'm pretty sure it is a problem.
I am waiting for rebuild kit.

Testing pics again.
By the way...arrow is the correct way and float level is good.
I'm pretty sure the check valve is the problem since it's messed up again.

Another pic

Must be everyone is still out boating!

I was hoping i could get a confirmation that this is "most likely" my concern. It seems like the fuel would be pushed towards carb then pulled back through the open check valve by the action of the diaphragm and not reach the carb like it's supposed to correct?

Does any one think pumping the prime bulb could pop the valve? The valve does not look worn out and it takes a decent amount of force to pop it open like in the pic. Or...could it be something with the motor itself. Or...am i dealing with a rare situation that no one has an answer to, LOL?

No way that valve is going to work. When the kit arrives, just install the parts & it will likely solve the problem for good.

+ 1 on that.

Negative.

I have another carb soaking in a carb dip right now.

The fuel hose is extremely long so i'm going to shorten to the length it will use when operating. Once i had a dirt bike that wouldn't run without the choke on. I found an added inline fuel filter, removed filter and it ran great...just a thought.

I got the fuel pump rebuild kit today and installed it. I used the new gasket, spring, bigger disc, etc but no difference. I used pics in the Seloc manual so i know the check valves are correct.

Compression in every cylinder is right around 95 psi.

Runs great when i dump premix down carb.

This is really bumming me out.

Is that how your cleaning your carb or are you taking it apart? You have to take it all apart, pull the bowl, remove the float, unscrew the jet and blow all the channels where fuel flows from one part of the carb to the other with carb cleaner then clean out the ports of your jet with a piece of wire. If your just dipping it your not getting the rubber and nest pieces out of it and it will never run right.

I completely disassemble it then dip each half at a time. Afterwards I spray wherever I can with Carb clean er and blow it all out with air nozzle on my air compressor.

Double post

Remove the fuel hose from the carb and direct it into a coffee can. Pour a little gas into the carb & fire the engine off. The pump should deliver a few decent shots of gas into the coffee can. If it does - then the problen is the carb. If it does not, the pump is not pumping.

If the pump is not working, check the vacuum/pressure line that goes to the crank case. The hose delivers pressure and suction pulses to the pump. Is the vacuum/pressure line doing that? If not, it is either clogged, attached to the wrong engine fitting, or the crank case seal is bad.

A long fuel line is not usually a problem for these, the pumps are very strong.

curse wrote:

I completely disassemble it then dip each half at a time. Afterwards I spray wherever I can with Carb clean er and blow it all out with air nozzle on my air compressor.

Oh OK you had me nervous that you were just dipping it. I feel better now.

Update:

Primed using the bulb and glass bowl fills up.
removed fuel line from carb and squeezed bulb, fuel comes out.
Poured premix in carb and started motor, fuel pumps into jar.
After motor stalled i unscrewed drain plugs and fuel did drain out.

When i do try starting without pouring premix in the carb it acts like the fuel line is not even hooked up....no spitting or sputtering...just cranking over.

Other half of the other carb is soaking in the gallon of cleaner now.

Any other ideas? lol

I got it to run on its own but when it warms up it starts stuttering and eventually dies.
It runs good till that happens.
does it sound like points/condensor?
Thoughts please!

You really need to purchase a service manual if you havent yet done so. A factory shop manual can be bought off of ebay for 15 to 20 bucks. They can save you a lot of time on servicing any engine.


If the fuel bowl is dry after it runs for a moment, and you confirmed that the engine is pumping - the float adjustment is out of whack. Remove the carburator top. Invert the top and look at the top edge of the float. It should be paralell to the gasket flange on the carb top - and the float needle valve closed. This is with gravity pulling the float arm on to the needle valve. There may be a little metal tab on the brass float hinge. This is the low limit tab that keeps the needle valve from falling out when the float drops to the bottom. Be sure the needle valve moves freely, opens and closes correctly. If the float has a red dope coating on it, you must replace it with the newer type that has a clear sealer on it. The old ones will absorb gasoline and fall apart.

The low speed needle valves must be rougly adjusted to allow the engine to run good enough to get it fine tuned. I can't remember the roght setting on the low speed needles, but I think it might be 1 turn back from bottom.

If you eliminate the carb as the reason it dies after warming up - you need a coil. If the engine runs at all - the points & condenser are working. A bad coil will work OK when the engine is cold & will stop working when warm.

Thanks Bruce. Yes I have 2 different manuals...Seloc and Clymer.
I'm really trying to fix this without asking too many questions:)
Below is a pic of float level...float is new. Slow speed needles at 1 1/2 turns out and high speed at 3/4 turns out.

Bruce Gerard wrote:

If you eliminate the carb as the reason it dies after warming up - you need a coil.

If i replace the coil can i use a sharpie to make marks on the belt and pulleys for re-assembly or will i need to set the timing and synchronize it after repair?

Follow timing procedure per the manual. To save time, set the timing mark on the flywheel & block prior to tear down. Remove the magneto - do not move the flywheel while the mag is off. If marking the mag pully to the body will help you - may as well do that too. But you should check everything against the manual when done, as the last work on the engine may have been done incorrectly.

Thanks for the tip. The procedure itself seems pretty easy as long as i pay attention to details. I'm really learning a lot about old outboards.

Time to take to a shop "rolling eyes"

Well, i avoided taking it to the shop.

I checked timing again and found it was off a hair. I replaced some linkage with new and performed timing procedure again.

I took to the lake to start it instead of in the driveway and it started up without even choking it and it ran nice. I do need to replace the impeller before running it more since i smoked it while testing in the driveway. I found out muffs do not work on this motor...Doh!

Congrats at least it sounds like you found your problem.

Homebrew wrote:

and never give up.

^ ^ I took some good advice ^ ^

The front seat should be done by Monday and hopefully i'll get it out then.

curse wrote:

Homebrew wrote:

and never give up.

^ ^ I took some good advice ^ ^

The front seat should be done by Monday and hopefully i'll get it out then.

HAHAHA very cool. Can't wait to see it run.