1998 Johnson 200 Venom

[Carl Pylant]

Can someone tell me if these compression numbers are okay on this motor?<br />The motor compression is:<br />#1 100<br />#2 100<br />#3 100<br />#4 100<br />#5 98<br />#6 90<br />Mechanic told me that #6 running lower on that model is acceptable and normal. <br />Thinking of buying this on a 1998 201 ProElite.<br />Thanks!<br />Carl

 

[rickdb1boat]

Re: 1998 Johnson 200 Venom

Possibly with a little decarb on #6, the compression may rise. Otherwise, they are looking OK... Within 10% of each other..

 

[clanton]

Re: 1998 Johnson 200 Venom

The max between cylinders is 15%, number 6 is getting close. Service manual, or service bulletins does not reflect that lower numbers on number 6 is ok. Try decarb like Rick said and retest. You should also check the upper main bearing housing bolts, if the are loose, they should be replaced with new bolts using loctite red.

 

[Carl Pylant]

Re: 1998 Johnson 200 Venom

Thanks guys...any thoughts good or bad on this motor?

 

[MCM]

Re: 1998 Johnson 200 Venom

The good news is its not a Ficht, beyond that you may want to see if you could take it for a shakedown run so to speek.

 

[DHPMARINE]

Re: 1998 Johnson 200 Venom

I don't know how the compression was tested,but I start with #1 and work my way down.When the last reading (or readings) are low,I go back to #1 and retest.If it is now low,I know the battery is giving me low readings,not the engine.<br /><br />DHP

 

[Dhadley]

Re: 1998 Johnson 200 Venom

Youre allowed 15 lbs difference and youre at 10. Assuming you have the same heads on both sides, it not unusual to see the top cylinders slightly higher than the middle and the bottom slightly lower than the middle. <br /><br />We pretty much do the same thing DPH does. Run the numbers twice, in order to verify. We usually do one side top to bottom, then the other then repeat.