Possible fuel delivery issue

Goosehunta

Recruit
Joined
Jun 1, 2020
Messages
3
Hi. New here to this forum.
i am looking for some advice and guidance on a issue I have with my engine.
Boat is a 1985 or 1986 Sport-craft OSFF 222.
engine is a 1985 omc seadrive 2.5. (Vro is deleted)

symptom is engine starts great and idles perfect. Get wot and get on plane and run about 5k rpms (sometimes a little more) and will ride there for several seconds sometimes a couple minutes then the rpms start to slowly reduce to about 3k. If I leave the throttle at wot and keep cruising after a minute or so the rpms will slowly raise back up. But it may only make it to 4K or 4500 then does it again.

it seems to be a fuel starvation problem. I have been chasing for a few months now. So far I have done the following:
new fuel lines
new fuel pump (non vro pump pre mixing)
rebuilt and cleaned carbs with OEM kits
new filter water separator

also done due to other issues:
new timer base (cdi brand)
new stator (cdi brand)
new regulator/rectifier (cdi brand)
new power packs both (cdi brand)

sync and link done
timing done.
new water pump (OEM kit)
plugs and wire (OEM)

what else could cause the problem.
I know it’s said to be a bad idea to install an electric fuel pump due to fire hazards but I’m really thinking about installing one temporary to try and rule out a fuel starvation situation.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,881
What are the compression numbers ?------Model # is ?----Test run with a portable fuel tank and hose ?
 

Goosehunta

Recruit
Joined
Jun 1, 2020
Messages
3
Compression was all in the 80psi range. Highest was 85 and lowest was 80.
Engine model number is 1CBXCO

have not tried a external tank yet. Good idea cause I haven’t thought about it.
 

racerone

Supreme Mariner
Joined
Dec 28, 2013
Messages
38,881
Those compression numbers are not encouraging.----Perhaps test with another gauge.
 

Goosehunta

Recruit
Joined
Jun 1, 2020
Messages
3
I only have 1 which is a cheap one from advance auto I think. Iv had for years. I’m looking for a good quality one.
 

OMCseadrive

Recruit
Joined
Jul 22, 2020
Messages
1
Goosehunta?
Don't mean to jump in this topic without anything helpful but how did you find how many degrees your engine timing should be set?
 
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