1987 4.3L V6 GM 262 ci OMC Cobra distributor issue

[dshakhba]

Hi all!

I have a 1987 Sea Ray Seville 4.3 GM V6 OMC Cobra. Long story short I bought this boat from a guy who knew nothing about boats..he overheated the engine due to neglecting the impeller and not changing it for years. I had the heads removed and rebuilt the engine. Worked absolutely beautiful then one day the engine boggs down and doesn't rev above 2200 rpm. I rebuilt the carb, figured that would help. Adjusted the crap out of it after many tries and same issue. For a brief second it opened up and worked then didn't work again.

I removed the carb filter one day and noticed the boat works perfect until 2000 rpm, but after that any gas and the carb shoots out fuel! ... at WOT you hear a pop pop pop and gasoline shoots out of the carb and a lot. I adjusted the timing and made sure its 6 degrees on idle and its fine. This leads me to believe the distributor might not be advancing...any thoughts???? I have a feeling the timing is jacked up and not advancing because before it didn't even go into gear..i would shift into gear and the engine would die. Adjusted the timing and that went away...but the engine just doesn't go above 2000...once it goes above 2000, backfires through the carb and the rpm drops. Any input is highly appreciated...I am out of answers.

-Dave

 

[MRS]

Did you check fuel pump if the diaphragh gos bad will dump fuel back into the carb. Pull a plug see if it is black they will all be sooted up. Just going thru the same thing found my pump was bad, might not be your problem but something to check. I did rebuilt my carb. thought that was it fired it up and was watching carb. you could see the fuel being dumped back into the carb. at the top of the carb. from the clear hose that runs from the pump to the carb.
Mine is also 4.3 motor 86

 

[bruceb58]

Probably not your distributor but worth checking it no matter what. Get an advance timing light or use timing tape and check the RPM every 500 RPM and make sure it is advancing properly.

 

[dshakhba]

Thanks for the input guys...I will definitely check those out.

Another thing to add is the engine revs perfectly in gear out of the water...in the water is where I get the problem.

 

[dshakhba]

How can I check if the fuel pump is good or bad? Do I just replace it and see if it fixes?

Did you check fuel pump if the diaphragh gos bad will dump fuel back into the carb. Pull a plug see if it is black they will all be sooted up. Just going thru the same thing found my pump was bad, might not be your problem but something to check. I did rebuilt my carb. thought that was it fired it up and was watching carb. you could see the fuel being dumped back into the carb. at the top of the carb. from the clear hose that runs from the pump to the carb.
Mine is also 4.3 motor 86

 

[Bondo]

How can I check if the fuel pump is good or bad?

Ayuh,.... Welcome Aboard,..... There's a couple of ways,.......

The simple test is to unhook the fuel line from the carb, slip a rubber hose over the end, direct the other end of the hose into a catchcan, 'n roll the motor over on the starter,....

Ya should get a good solid blast of fuel, each time the motor rolls over,...

Another way is to plumb in a pressure gauge, 'n check for 4 to 6 psi,....

 

[bruceb58]

Another way is to plumb in a pressure gauge, 'n check for 4 to 6 psi,....

That's what I would do. Gauges are pretty inexpensive.