1987 Mercrusier 4.3L with Mec fuel pump issues?

[jmorgan18]

so here is goes, I have 1978 Sea-ray serville with 4.3 in it starts and runs great. BUT the flame arrestor on top of the 2br carb smells bad of gas value covers smell like gas side of carb looks like gas is on it, top of carb is covered with gas. heres the kicker oil smells like gas.

pressure on all cyi are good
does not smoke at all
checked the tube from carb to pump does not look like gas was in it but looks like it has been at one time.

i dont think gas should be all over the Carb and flame arrestor, would the lines from the valve cover be sucking the gas in the valve covers, Im lost and cant seem to find where the gas is getting in the oil HELP.

 

[Bt Doctur]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

bad fuel pump diaphram,

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

bad fuel pump diaphram,

Will that cause the fuel covering the top of the can and the arrestor and fuel in oil?


also how do i fix it?



Thank you!!!

 

[MikDee]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Carburetor float stuck open.

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Carburetor float stuck open.

Is there a way to verify or to troubleshoot to find out if its suck.


Im a electronic guy newbie when it comes to this carb stuff

Thanks!!

 

[wrench 3]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Will that cause the fuel covering the top of the can and the arrestor and fuel in oil?


also how do i fix it?



Thank you!!!

It will cause the flame arrester to smell of gas but shouldn't put fuel on the outside of the carb. It shouldn't put gas in the oil unless both diaphragms have ruptured.
Take a close look at the clear plastic line to the carb with the engine running.
If there is any gas moving up the line, replace the pump.

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

any idea why oil smells like gas. and extra gas all over top of carb

 

[Bt Doctur]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

the oil smells like gas because gas is getting into the oil. gas on the carb is either a ruptured diaphran or a very high float level or a leaking float

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

the oil smells like gas because gas is getting into the oil.

Right but I cant pin point how.???

I dont think its the rings since I have no loss of power or smoke.

could a injector be leaking in to the cylinder the slowly leaking down a ring. ( never heard of that happening)

but im also lost on this issue

 

[Bt Doctur]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Now were all confused, first its a carb, then an injector, When a diaphragm is ruptured ,the gas enters the engine from the fuel pump body
directly into the crankcase.

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Sorry if I confused anyone, im just thowing our idea's

I understand if the diaphram is busted the gas would be in the oil,

so to check that ill need to do it check the tube from pump to the carb while running to see if it has fuel in it?

and if there is no fuel in the tube. I need to look at Float and needle?


Thanks for all the help!!!

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Update to today I went out and found the connection on the bottom of the fuel pump was 100% clogged cleaned that out and started the boat and watched for gas coming up the line, seen non shut the engine off pulled the line off the bottom of the fuel pump no gas in the line... im lost could the pump still be bad if its not pushing gas out that clear hose?

 

[MikDee]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Then maybe the anti-siphon valve is clogged, or bad,,, it's usually just off the fuel tank, plus you need to check the pick up tube in the tank, which probably has a screen on the end to check also.

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

anti-siphon valve and pick up, my issue is gas in oil would this cause that?

 

[Bt Doctur]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

There are only 2 possible entries of gas. The carb and the fuel pump. A high fuel level/defective needle /seat/float but this would be telltale by black smokey exaust, gas smell, wetness at carb. The fuel pump entry sometimes is not visable .The vent could be clogged internally by now not letting fuel into the clear hose. If you have eliminated the carb by not seeing overflow, rough running, black sooty exaust then suspect a bad fuel pump.
Remove the fuel pump and look ,smell inside the area where the pump arm is. carefully fill the pump arm area with tissues, reinstall, do a test run, remove pump and check tissue. there should only be oil stains on the tissue ,not gas.
The thing to remember is that with enough gas mixing with the oil you HAVE A BOMB WAITING TO GO OFF. The vapors exit from the valve covers, fill the engine compartment and a loose sparkplug wire is the ignition.
I`m sure some of the older persons here will confirm seeing the valve covers blown off motors and sometimes the oil pans

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

k tomorrow ill remove the pump is gasket between it and the block?

 

[MikDee]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

Update to today I went out and found the connection on the bottom of the fuel pump was 100% clogged cleaned that out and started the boat and watched for gas coming up the line, seen non shut the engine off pulled the line off the bottom of the fuel pump no gas in the line... im lost could the pump still be bad if its not pushing gas out that clear hose?

Well, you said there was no gas in the line going into the fuel pump? This comes from the fuel tank, no?

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

no there a line from fuel pump to carb that is a vent for fuel that could be leaking from the pump

 

[jmorgan18]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?



This is what I found in my fuel pump, there was also some rust and you could tell where fuel was leaking out of. Im assuming this is REALLY old gas that has gelled under the diaphragm..

 

[Bondo]

Re: 1987 Mercrusier 4.3L with Mec fuel pump issues?

View attachment 230536

This is what I found in my fuel pump, there was also some rust and you could tell where fuel was leaking out of. Im assuming this is REALLY old gas that has gelled under the diaphragm..

Ayuh,.... That's the engine oil side of the diaphragm,...