compression numbers please

ronward

Petty Officer 1st Class
Joined
Jun 24, 2013
Messages
346
does anyone know what comp should be for an 85ESL73M? right bank is 110 both cylinders. left bank is 105 both cylinders. sound like a good motor? has been sitting and probably needs a de-carb to bring up the comp numbers. any takers?
 

boobie

Supreme Mariner
Joined
Nov 5, 2009
Messages
20,826
Re: compression numbers please

For a motor that old they sound okay. Just make sure you do a good decarb on it. I always use BRP engine tuner and have had good luck.
 

ronward

Petty Officer 1st Class
Joined
Jun 24, 2013
Messages
346
Re: compression numbers please

thanks for the reply. already had the motor running and it runs pretty good.
 

emdsapmgr

Supreme Mariner
Joined
Dec 9, 2005
Messages
11,551
Re: compression numbers please

When new, the compression was probably in the 125 range. Your engine should still run with those numbers. Not unusual for compression to vary up to 5 lbs between heads, due to the way they were originally bored at the factory-so that's normal. Agree, a decarb may help the compression.
 
Last edited:

ronward

Petty Officer 1st Class
Joined
Jun 24, 2013
Messages
346
Re: compression numbers please

Put seafoam in and let sit for a week. Compression now is a solid 125+ on all four. Now to the carbs and pump impeller.
 
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