1993 Johnson Oceanrunner 150HP

Big Fish Billy

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Heading out tomorrow to look at an 18' CC with the above motor. It looks well taken care of, do you guys know of any inherent problems I should be on the lookout for?

Thanks,

Bill
 

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Chris1956

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That should be a lot of power for that boat. Sometimes those motors do not like to start easy and miss, when restarting after an hour or two. If that happens, advance the throttle in neutral, and crank it up. Let her run until she runs clean.
 

boobie

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Do a compression test on it and check the lower unit for any water. And then give it a good lake test.
 

Big Fish Billy

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Thanks guys, took it for a ride, definitely have to be careful with the power, went over 35 knots on the gps with plenty left. Did a compression test, they were all at or around 95, which seems low to me...what do you guys think. Lower end fluid was clean. Luckily I brought my tester and the batteries aren't charging, so the guy is going to put a rectifier in, the motor just had a new power pack put in. All in all it's a nice boat, new Neptune t-top, 2008 roller trailer, and engine for $5,000. The compression bothers me though, are those numbers normal or low? Thanks, Bill
 

racerone

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You say it had lots of power.---Then you say you are worried about the " apparent low compression "---Perhaps your tester is reading low.---They are all different.
 

Big Fish Billy

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A lot of older engines run well with low, but even compression. Just asking what the correct compression should be 140? 130? 120? 110? if it's 100 and it reads 95, I'm happy....if it's supposed to be 140, I'd say I have some work ahead of me....just asking? Bill
 
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That's a looper, OMC normally put idle relief ports in them which makes the compression read a bit low at cranking speeds.
 

Big Fish Billy

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I really don't know what looper means, I found an old thread on here that says 100 is good so I'm feeling better, thanks....
 

boobie

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The compression you have is normal for that motor. Seen a lot of them that way and they ran good.
 

Big Fish Billy

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Thanks, I don't mind working on them, there's a lot of great info here, guys walked me through rebuilding my Force 40, this is a huge motor for an 18' boat, scary actually, I'll run it until I have problems, then rebuild as necessary, thanks for all the help....Bill
 

Big Fish Billy

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Ohh...it's there, I'm sure it'll hit the pins from time to time...I have to admit though, at 63, I've traded some sense of adventure, for the "thrill of victory"....when I turn the key and it starts and runs dependably.....
 

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Chris1956

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Depending on the model number, that motor could have a water cooled voltage regulator ($250 or so), instead of a rectifier. Make sure the PO replaces the right part. The water cooled VR is located directly behind the flywheel, under a plastic cover.
 

Big Fish Billy

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Hi Chris, thanks, the motor number is J150EXETO...the sellers friend that is an outboard mechanic and going to do the work, says it is under the power pack. I'm definitely going to be sure it's charging properly before I take it. I think I looked the part up on Crowley and you right on with the price. Water cooled, I hope it didn't blow due to engine overheating....
 
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