150EXET Compression

N

No-Sail

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Wanted to check on compression specs for 150 EXET Johnson Oceanrunner. (Think engine was first year for the 150.)
 
tashasdaddy

tashasdaddy

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Re: 150EXET Compression

the main thing is that they are within 10% of each other, would like to see above 100 psi. each guage reads differently, so there is not a published prefered compression.
 
JB

JB

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Re: 150EXET Compression

If EXET is part of the model number, it is a 1993, a lot newer than the first 150. My first 150 was a 1983 and I don't think that was the first one..

Those big V6s often show lower psi than most other models. Depending on the C guage, conditions and technique I would accept 90psi +/- 9psi as a good, healthy engine.
 
D

Dhadley

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Re: 150EXET Compression

He's talking about the 60* 150s. The first was in 1991.
 
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No-Sail

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Re: 150EXET Compression

First time on a forum so not sure if this is appropriate, but thank you.
 
D

Dhadley

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Re: 150EXET Compression

Very appropriate, good question. That's what this forum is for. Is this a motor you're thinking about buying?
 
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jonesg

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Re: 150EXET Compression

No-Sail said:
First time on a forum so not sure if this is appropriate, but thank you.
Click to expand...

For comparison, mine is a 1994 Johnson 150 looper, compression is approx 85psi across all 6 cylinders, runs strong.
I don't know but suspect they are short stroke motors to keep recip' mass down. Good engines as long as they are maintained like other 2 strokes, rebuild carbs, change gear oil etc.
 
Benny1963

Benny1963

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Re: 150EXET Compression

im have a 1983 crossflow 175 fresh 110 with the thin head gaskets and
xp heads
 
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Dhadley

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Re: 150EXET Compression

It's not so much the stroke (the 60* loopers are the same stroke as the 90* crossflows) but rather port timing. Among other design differences.
 
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