1987 EVINRUDE. SPL88 troubleshoot

racso

Seaman
Joined
Jun 29, 2014
Messages
56
Well guys after playing arround with this motor ... I have replaced the rectifier and battery i now need an rpm gauge it dint work since i got this boat and is not working with the new rectifier either so i think is bad..... Now a while ago i was sugested to do a compression test and a spark check well i got the testers from an auto parts store and this is what i got on compression stardboard side top cylinder i got 115 and 120 at the bottom the port side top one got 110 and bottom was like 105-107 being this one with lowest reading what you guys think ....and spark it has good spark in all 4 cylinders ....now still when idle i dont like the sound it is not a smooth continues sound . It is kind of ruff and like it lacks air or something until it warms up a litle it kind of picks up i gues its ok so am not goin to bother much any more ....thanks for all the helpfull tips to all
 

fireman57

Captain
Joined
Aug 24, 2004
Messages
3,811
Have you pulled and really cleaned the carbs? Might cure it for just your time and no money. Your compression numbers are right about 10% of the others so you are fine. Compression gauges vary so much that I am going to assume these numbers are actually around 5% off.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
It's not unusual for there to be a compression difference of 5-7 lbs between heads, due to the way the blocks were originally machined at the factory. You might want to decarb the engine. Get a can of Engine Tuner from your local Bombardier dealer and follow the instructions on the can. Possible to pick up a few lbs of compression and it may idle slightly better.
 
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