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1995 force (mercury) 9.9 hp. Serial #OE105918

How many times you do the test?
What gauge?
The screw in or the old push in ?
The screw in is way superior

Harbor freight tools are JUNK!!!
Bad results on comp tests.

Get another gauge.

I just bought(got it yesterday) a borescope from eBay. $10
Works great.

You can check the cyl. for scoring with a piece of wire from a hanger.
It can tell you if there are big scrapes.

If it's really low on comp, and the walls are scored, then you might be able to get it bored and save the motor?

But you can do more damage and make the head useless.
 
I pulled the head on my 1995 force 9.9. The cylinder walls were smooth, no scoring. I have a good compression tester, (not Harbor Freight). Still showing about 40 psi in the top cylinder and 80 psi in the lower cylinder I am wondering it the kill switch could be the culprit. It is very hard to get parts for this engine. If I sell it as a whole unit. Is there any interest?
I live in CT. Thanks
 
1995 Force 9.9. My problem started when I started this engine with fresh gas and oil, new lower unit fluid and a new impeller. Engine started right up. Drove it for about 10 minutes at full speed. The engine cut back to about 1/2 speed. After 10 more minutes the engine died. There was no overheat situation, just died. Kill switch, Coils? About 100 dollars each. How do I test the coils? Thanks
 
outboardignitiondotcom has test procedures for your motor.
CDI Electronics has a tech line that answers questions.

You test for spark?
Try swapping coils around if there is no spark on one.

If your comp is really that low?
Try another gauge?
You remove both plugs to do the test?
 
I found the problem for the low compression in the top cylinder, BLOWN HEAD GASKET. It's about a $17.00 part, on order now. I hope this is the only cause. Ihope the rings are ok.
Thanks,
Sullmate
 
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