1998 Johnson 200 Venom compression check

[cbaker10]

Hey, I have a 1998 Johnson 200 Venom. I just did a compression check and I was wondering if anyone could tell me what they think, they seem a little low to me but I really don't know what they should be. The two top cylinders were 60 and 90, the two middle cylinders were 60 and 65, and the two bottom cylinders were 55 and 60. I took these readings after I let the motor run and warm up. I would appreciate any input?

 

[Bob_VT]

Re: 1998 Johnson 200 Venom compression check

Have you de-carbed that motor? I would do a full decarb and check again. Did you hold the carbs wide open when you cranked it for the compression test? Were ALL the plugs removed?

So here's the route I would take. Decarb, new spark plugs (since decarb routine is nasty on the plugs) then a compression test.

 

[cbaker10]

Re: 1998 Johnson 200 Venom compression check

No I have not done anything to the carbs. And no I didn't hold the carbs wide open, I thought you just had to crank it. And again, no all plugs were not removed, I unplugged all of them but I removed them one at a time. So, what do you think? This is the first compression check I've done.
Thanks

 

[boobie]

Re: 1998 Johnson 200 Venom compression check

Pull all the spark plugs out, pull your kill switch so there's no spark and do it again. What Bob_VT meant by a decarb was to run SeaFoam through the mtr to free up the rings. Do it again and get back to us.

 

[cbaker10]

Re: 1998 Johnson 200 Venom compression check

In that case, I did decarb the motor, I didn't use seafoam, it was a Johnson and Evinrude brand carb cleaner. I ran a whole bottle through it. I will pull all plugs and try it again tomorrow. Thanks

 

[boobie]

Re: 1998 Johnson 200 Venom compression check

If you used John/Evin Engine Tuner that's good stuff. Hope you followed the directions on the can.