Rough Idle After Decarbinization

[Shadoprizm]

2 days ago I completed a Seafoam shock treatment on my 89 Johnson GT100. The treatment seemed to go well and the engine was idling steady at around 800RPM after burning roughly 1.5 Gal of Seafoam/Gas/Oil mixture. A few hours later, I noticed a puddle of gray sludge which leaked from exhaust - I suspected this was just un-burnt fuel/oil and water. I then left the engine to sit and soak.

Today I attempted to start the engine for the first time since the treatment and it was difficult to start and stay running. When I finally was able to get it running, it would stall around the 1200-1000 RPM range and was idling rougher than before the shock treatment.

Is this normal behavior after a shock treatment - or am I missing something? Should I just let it run for a period of time and see what happens?

 

[oldboat1]

Not much choice now but to run it and try to clear. Use fresh fuel with no additives (50:1 if premixing). Operate in the lake or using a barrel (idle or high idle only in a barrel).

 

[Shadoprizm]

Thanks for the response Oldboat 1 - I will give it another shot, I was thinking there may just be alot of residual Seafoam mixture and carbon that needs to be burned off...It certainly was a smoke show when I was able to start it today.

 

[flyingscott]

Change your plugs.

 

[racerone]

Do a compression test on this crossflow engine.---Post your numbers.

 

[Shadoprizm]

flyingscott - good call, I will do this.

racerone;

cylinder 1 was @ 90psi before the decarb....

however after decarb, it came up slightly;

cylinder 1 = 103
cylinder 2 = 122
cylinder 3 = 120
cylinder 4 = 120

not within 10%... but close ;-)

 

[flyingscott]

Cylinder #1 is not good pull off the transfer port covers and look inside. Or just pull the head on it.

 

[racerone]

Pull the head and post a picture !!----Broken rings is very common !----I see this failure all the time.