Need help !

[shu9265]

OMC- 260, 350 cu in. Has new plugs,wires, cap, rotor, new fuel pump, carb rebuilt, new coil.

Problem is when traveling at high speed or even trolling for that matter the engine just quits! My first thought was bad coil. So I changed that.

Still have the same problem. (But have really good spark)

When the engine quits, we have to wait for a few minutes before it will restart.

Next, removed the hatch cover, to allow more air into engine cover. That seemed to work for the first hour. Same problem again.

Checked the timing. All good. Runs Great! Same problem.

Do any of you folks have any idea's as to what may be giving us these problems ?

The engine acts like it is starving for fuel, at speeds over an idle of about 800 rpm's

This is really screwing up our fishing in the LOC tourney going on here in NY.

[anthonyyost]

fuel filter?

[tray19682005]

I agree , fuel filter, may be second one on carb. Worth checking should be a easy, low cost fix! But alowing more air in to cool motor doesnt make sence unless its running to hot. Or check oil make shure its not milkey colored then it could be blownhead or intake gasket. good luck

[nickoftime]

check your vent tube could be getting a vapor lock just like a car would

[1mainiac]

Had similar issue 3 years ago truned out it was a bad set of plug wires which were new. But in what you describe I would be more suspect of a fuel problem sounds a lot like vapor lock which is caused when the fuel in the lines get too hot and turns to a vapor instead of a liquid since the pressure remains it will hold the float open but cannot get actual fuel into the carb. Try putting a wet rag on the fuel lines the evaporation from the wet rag will cool the fuel and stop any vapor lock if this fixs the problem you need to find a way to route cool air onto the fuel lines or a way to shield them from the heat. Another possibility is you have a bad fuel line or the fuel vent to the tank is plugged. Years ago a friend of mine chased a fuel problem in a snowmobile for months it was a dead bee in the gas tank when the tank got low enough it would suck the bee into the fuel intake and kill the motor let it set a min and it would restart and run perfect.

[1mainiac]

Any time I suspect a fuel problem I run it on a portable tank if the problem goees away you know where to look

[Priority1]

The fuel today is tough to digest for carburetor engines. Have the fuel lines been changed recently?? The alcohol in the fuel deteriorates the older fuel hoses. There could be bits and pieces of fuel hose plugging things up. Even if you find a different problem, it would behoove you to change the fuel line. Add some Seafoam to the gas.

[usmcpaul]

It kind of sounds like you have eliminated everything except fuel delivery. I would replace the filter and ,make sure the fuel pickup in the tank is clear and there is not sediment at the bottom. It sounds like you have to let it sit for a while, then sediment then falls down and lets the fuel flow again.

Or if the tank vent is clogged it will create a vacuum and kill the motor. In either case the motor would bog down and then quit. You might try running it with the cap off as long as no water spray can get in.

Other than that, I would be checking for a broken wire. When it heats up it looses contact. The motor would act like you turned the key off.

[shu9265]

Thank You All for the responses. Looks like I will be sitting at the dock tomorrow changing the main fuel line.

I thought it was the filter also, but when I pulled it and put a new cartridge in all was clean. I still put the new one in.

[shu9265]

Almost forgot to ask, is there an automotive fuel pump that is the same as this one?

Like maybe 70's Camaro or something with a 350 in it ?

[diesel]

your problem is sounding more like a electrical issue is in the starter slynoid. have had problems in the past with chevys. the exhuast is right on top of the starter and the heat causes the sylnoid to over heat and then nadda. the reason i am looking at this is after you said you open the hatch it help out that would not most likely help a vapor lock issue in the fuel system.

the starving for fuel problem i would make sure you dont have any forgien matter

(like a mexican) a plugged idle circut jet or a plugged main jet on the carb.

[diesel]

and i also forgot pretty much all gm mechanical fuel pumps are the same but the marine applactions have a water/fuel seporater on them on the out-flow side soooooo if you put one one when replacing the fuel pump that didnt have the water/fuel seporater you could very very very well be having the issue from water in the fuel.

my FIRST action would be try some sea foam cause come to think of it i had the same issues with my uncles boat last year and sea foam cleared it out.

[Line Dancin]

i had a very similar problemchased all the same items. In the end took it to johhnsons supreme in ludington. Found out it was the distributor assembly. to upgrade from point to electir was only 60 bucks more. did it and no more problems and no more screwing with points. Ths vent plugged and rusted the whole assembly all to heck causing mass problems.

[Priority1]

Almost forgot to ask, is there an automotive fuel pump that is the same as this one?

Like maybe 70's Camaro or something with a 350 in it ?

Do NOT under any circumstances use an auto fuel pump on a marine engine. If the bellows fail on a marine fuel pump there is a safety line that prevents fuel from dumping into the bilge.

Auto Starters and Alternators should not be used in marine applications. The marine ones have spark arrestors to prevent a possible explosion.

I rebuilt my mechanical fuel pump a couple of years ago.

Edited May 2, 2010 by Priority1

[special x]

I would say you are suffering from a heat sink problem in the ignition..

Install an electronic dist..part # CRU-22752K..This is a Delco dist and all the parts for it except the moduel can be bought at any parts store..I have been running these dist for over 6yrs and they are bullet proof..

[Lemon Chill]

You should us the marine type that has the safty sight hose for failed diaphram if a fuel pump fails it can fill the crank case with raw gas and possible explode.MK

[shu9265]

I GOT IT ! ! !

The mechanic at the Marina was bound and determined that the carb was not working properly, and that I needed to replace the fuel pump for $350.00

I went through the whole thing, checked Everything!

This is what I found. The main fuel supply line from the tank was aged, cracked and checked. Replaced that ($15.00)

All was good for the first 1/2 hour. Then it started the same thing over again.

So, I unhooked the fuel line from the tank, and put it into the kicker tank.

Ran GREAT ! ! ! Not even a hiccup.

Got back to the slip, and started digging.

Removed the fuel gauge, and used a flashlight to have a look see....

Very little water in bottom of tank, so I moved the pickup tube up by 1/2 inch.

Cleaned the screen in the pickup tube, and reassembled.

Hehehe, it now runs perfectly !Must have been just enough junk in there that it was causing the engine failure.

Want to say Thank You to all the members here that gave me there suggestions and offered there help.

And Frank, I was just asking about the parts, I know better! Thanks.

[Priority1]

Bill, I'm glad you got it going.