88hp johnson outboard motor

"I recently purchased a used 1

"I recently purchased a used 1994 88hp Johnson motor before my first trip the compression was about 125 psi 3 cylinders and one was about 120, however after first trip I burned about 75 gallons of fuel and returned with a compression of 120 psi 3 cylinders and 190 on the one. The engine appears not to have a cooling problem is this problem.

When I bring the motor in a elevation of 3,800 the spark plugs run a little rich and the when I punch it has allot of hesitation, when I put new plugs in it works good for a while, however it does not take long before the hesitation returns. Other changing the jets in the carb is their a plug you would recommend, I’m presently using a NGK standard plug."

"Ql77JC4 champion is recomende

"Ql77JC4 champion is recomended for that engine gap at 0.30,sounds like you may have a bigger issue wiih compression.double check comp in all cyls,if needed pull the heads/look for damage scoring,excissive wear etc."

"Mr Harris,

I did recheck t

"Mr Harris,

I did recheck the compression readings were the same, however what would cause the premature ware?"

"i would not call it pre matur

"i would not call it pre mature wear,could have had the issue before you got it,a fresh crossflow with average use should have redings around 130 120 psi,any number of things can happen,carbs too lean, failing gaskets, old crank seals.you might want to check that head gasket as it may have an issue.try to resolve the problem before you run it any longer as that cyl will let go ,and will be costly to repair.
right now you can take the short route and do rings /gaskets bearings(a quick fix on that cyl)
depends on what you have to spend,the best would be to do them all the same at the same time."

"Use the Champion Q plugs NOT

"Use the Champion Q plugs NOT the NGK's

I would take the head off and inspect. Sometimes excessive compression reading is due to carbon build-up in the combustion chamber. You may want to run some power tune (mercury spray can). Spray it in per the instructions, let soak for about 1 hour then run her WOT for 5+ mins. Then check compression again."

I'm a little confused when

I'm a little confused when you say excessive comppession the readings have changed to be lower. Should I use the Spray before I pull the heads and what is the torque for the bolts?

Merc's Power Tune or anoth

Merc's Power Tune or another brand's Decarb can/should be run in your motor asap. The stuff is amazing if you follow the directions.

The Power Tune has a bit of a noxious odor though so even if your outside keep up wind of the motor. It works pretty well though.

The "Q" plugs are great. I had 2 sets of NGK's and the switch back to Champion was noticeable.

"I read 190 compression, I cal

"I read 190 compression, I called that excessive. If you are comfortable you are not going to damage your motor than run the spray first. Stuff works Great.

Let me check on the foot LBS for the bolts...also there is a bolt tightening sequence you should follow."

My apologize the reading on th

My apologize the reading on the one cylinder is 110 psi

"What Cylinder number is the 1

"What Cylinder number is the 110psi?

You may have a stuck T-stat which in turn would make your motor run hot and could break a ring. Don't run it yet. You may need to pull the head to inspect. If you have the tools and are comfortable in removing the head be careful. If a bolt seems tight and doesn't want to budge then stop, you will have to heat up the bolt and ease it out. Nothing can make that job more frustrating if you start breaking bolts (especially inside the block).

If 3 are at 120 and 1 is at 110 that is still good. all 4 psi's readings are still within tolerance.

What makes you think its an overheating problem?
Did you hear anything start to rattle inside the motor or exhaust? (that could be a ring)."

"One thing I noticed when I ra

"One thing I noticed when I ran the motor about mid throttle I heard a clanking noise hard to explain, however when I throttle up to 3/4 throttle or full it went away, I was thinking it may be the elevation. I did constantly check the heads for overheating and I never really felt a problem the top of the heads were not hot, I could hold my thumb for about 15 or more seconds.

I will pull the heads on the one side and thanks for the tip about the bolts, I was thinking of that also I perform all my own work on my vehicles.

If it was a ring would the compression be really low.

I just hope I don’t have any serious damage."