Fuel smell from exhaust

sgajan

Seaman
Joined
Apr 16, 2005
Messages
74
HI,
I have a 1988 3.0 omc 140hp engine that has an electronic distributor. There are a few current issues im having with it.

1st. I have alot of fuel smell when in reverse or just idling along. The back of the boat has black deposits on the hull from the exhaust also. And i found a bit of fuel in the oil. I checked this because i was getting a blowby out of the vent on the valve cover. I have rebuilt the carb with a holley kit to specs. Removed the spark plugs and did a compression test on it. I got around 175 on all the cylinders. Im guessing thats ok? I have changed the plugs and wires,cap and rotor. With this said. Im not sure why im still running rich. Would any other ignition parts cause this? Would a bad cylinder head IE; valve seats etc..cause these conditons?

2nd.
The boat does get out of the water like a scared cat BUT the RPM wont go over 3200 at wot.(prop is a new 17").
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Fuel smell from exhaust

Check to see if the choke is opening fully. If not, the choke coil may be bad.
You may also have a defective fuel pump, which could be pumping raw fuel to the carb through that clear hose, and causing it to run extra rich.
 

sgajan

Seaman
Joined
Apr 16, 2005
Messages
74
Re: Fuel smell from exhaust

Yeh i thought maybe the choke was the culprit at first but its opening when needed. I should have posted that its working.

The clear hose doesnt have any fuel in it or signs of any fuel.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Fuel smell from exhaust

It may need a carb rebuild, or even a tuneup. You can pump fuel into them, but if the ignition doesn't burn it, it's not going to run right.
A compression test would be another test of how the engine is.
 

sgajan

Seaman
Joined
Apr 16, 2005
Messages
74
Re: Fuel smell from exhaust

Everything that ive done to it to try and correct the problem is in the first post.
The carb has been rebuilt.
compression is around 175 each cylinder
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
70,957
Re: Fuel smell from exhaust

I have rebuilt the carb with a holley kit to specs.

Ayuh,... Runnin' Rich is runnin' Rich,... Maybe you Missed something....

Float level a tad High,..?? Boats Don't sit level ya know....
 

sgajan

Seaman
Joined
Apr 16, 2005
Messages
74
Re: Fuel smell from exhaust

I took it apart and looked around. Im not seeing enything out of the ordinary. the 2 idle air screws were set back to 1 and 1/4 turns out on each of them. I originally rebuilt the carb cus the float pin was rounded off and when the boat was on a ramp i could see fuel just pouring into the intake one day when it wouldnt start on the ramp. since the rebuild it hasnt leaked a drop. im guessing that the jets are correct. would anyone know the correct size jets for this machine is? That was one other thought i had. perhaps the jets were too big for the application. When i got the boat and after some reasearch i found the old owner boogered a few things... so i wouldnt be surprised if the jets are wrong. LOL thanks for the help so far tho
 
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