1985 Evinrude 185, 2 stroke, Engine shut off at idle (help)

[Jess5ben]

85' Evinrude, 185hp, 2 stroke
Model No: E185TLCRS
Serial No: J0425266
Outboard came with the boat I bought 3 months ago. Took it out on a lake for a week and had problems. Very different to start, had to idle very high for a few minutes then slowly ease to idle. Most times the engine would die at idle and sometime it would stay on. As the week went on the engine shutting off got worse. I would throttle down when approaching a fishing spot and the engine would shut off. Plenty of emergency anchor throws! Sometime I could not get the engine to fire back up for awhile after the engine shut off. Today I performed a compression test on a hot engine: four cylinders tested at 80 psi, one cylinder at 73 psi and the worst cylinder at 65 psi. I can not find compression specs anywhere to save my life to figure out if it's worth fixing. Figured I would start looking at the fuel lines, filter and pump if the compression is good. I would take the engine to a mech to address the low cylinder, but would really like to wrench on the rest. Please help!! Thanks!

 

[racerone]

You have a bad gauge perhaps.----But I say pull the heads and inspect.----Sounds like a complete rebuild or new motor is in your future.

 

[oldboat1]

Any overheating on your watch? should run at around 140F on top of heads -- change out the impeller anyway, as it's a new motor to you. When you pull off heads to check for scoring, refinish the mating surfaces and install new gaskets whenever you get ready to put it together.

 

[greggilo]

Minimum compression should be 100 and all cylinders within 10%; but the engine will run at lower values.
I am currently rebuilding two motors with compression around 80. They would run fine and idle but hard to start.

 

[racerone]

Motors will run with lower compression.----They won't perform.-----A nascar racing team would never be a winner with a motor that has lower than new compression !!!

 

[ct1762@gmail.com]

my guess is as suggested above: motor got hot. REALLY HOT! those compression #'s are not good. maybe you get lucky and it was some water in the heads or fuel, but not looking good. pull heads.

 

[CaptnKingfisher]

I agree low compression results require an overhaul, so before going any further verify with another gauge.

I wouldn't expect you to be stalling in neutral with those numbers however. If you want to do a little bit more hunting use an adjustable spark tester and measure how strong your spark is at each cylinder. Anything less than 1/2" or 7/16" I'd classify as weak spark. If you've got weak spark report back and we can guide ya through troubleshooting.