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Compression Question 1989 20 horse Johnson

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pbartrum

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Hello, I just bought a 1989 20 horse Johnson (TE20CRLCEM). I am going through it now, I rebuilt carb and fuel pump already, Next is lower unit reseal and water pump, My question is about compression. I am reading 70 psi in the #1 cylinder and 72 in #2. I can't find any information as to what is the acceptable range before you need to think about new rings. Right now it starts in one or two pulls, I'm just trying to figure out if the engine is getting tired or if I have a few years in it. Thanks,
 
You might invest in a better quality compression tester.-----Or remove bypass cover to look at pistons / rings.----And new rings on old pistons is a mistake on these motors !
 
racerone said:
You might invest in a better quality compression tester.-----Or remove bypass cover to look at pistons / rings.----And new rings on old pistons is a mistake on these motors !
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I bought a can of engine tuner, I was going to try that first before I tear into the motor, I want to do all the simple stuff first and see if that helps. Question, why do you say get a better quality compression tester? is 70 psi telling you something that I am not seeing?
 
racerone said:
???---Some will argue.-----But , you would want to see numbers around 110 / 120 PSI in my opinion.
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Well that will give me something to go by, I was looking around online and was able to locate a rebuild kit for this engine. might be something to do over the winter. Thanks for the info.
 
Did you read post #2 ??-----There is a " painless " way to determine condition of pistons / rings.-----Remove the bypass cover !
 
Welcome to the forum.
A view of the rings, piston and cylinder walls is really what it's all about. There is no reason not to do this when compression is below 100 psi on these. I recommend these motors for anyone that wants a reasonably lightweight and reliable power/workhorse. Lower units can develop leaks and owners don't catch it in time. The powerheads are pretty nicely made. They pumped them up to 35 hp. I run twin 25's and 30's at our camps in NW Ontario. Only failure I've had in 35 years is a stator....Ha! And one theft!
 

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