johnson 200 compression

[ranger1850v]

Is 70s comp to low on an 87 gt200? And I have a racing mid and lower unit with an exhaust relief on the mid. Is stock jets acceptable?

 

[boobie]

Re: johnson 200 compression

Sounds a little low. Try another compression gauge.

 

[JB]

Re: johnson 200 compression

That is a low compression engine. 70-80psi is acceptable.

 

[ranger1850v]

Re: johnson 200 compression

I know my gauge is good. But its really slow to plane and a lot of the times boggs and won't plane. I wandered if my low compression was why.

 

[Faztbullet]

Re: johnson 200 compression

I have a racing mid and lower unit with an exhaust relief on the mid.

You have a 15" midsection?? Sounds more like a stock midsection with a bolt on "cow bell" and nosecone added. It will be slow out of the hole as it has no back pressure and on a heavy ranger just hurts it more.. 70 psi is pretty low on a 2.7L engine and from your other posts the only way it would turn a 27pitch would be in a 4 blade shooter and still thats a little much., a 3 blade with your set up should be a 24 pitch raker or 22 turbo and cap the exhaust off as all it does is makes noise and add very little hp unless you turn it over 6500rpm which it wont live at.

 

[ranger1850v]

Re: johnson 200 compression

That's just what the guy told me when I bought it. I took to local mechanic and he said someone has tried to make it a racier engine.ha. Idk what a cowbell is but it doesn't look like someone cut into the midsection and I think it is a 15". Lower unit has the lower water pick. I tried doin a decathlon today and now I have 60-65psi on one bank. I took it out and it was the same thing.. it'll almost act like it'll plane then it stumbles and misses and falls on its face. Then if I try to open it up again it'll just boggle down and die. Also noticed none of the guts are in the airbox?

 

[Faztbullet]

Re: johnson 200 compression

If it is a 15" midsection you would have to jack it down so lower unit is is water ,cowbell is just a bolt on exhaust snout.
http://www.bobsmachine.com/products/engine_exhaustHousing.cfm

lso noticed none of the guts are in the airbox?

Need to check jetting as gutting the airbox makes em run leaner...

 

[ranger1850v]

Re: johnson 200 compression

So maybe the lack of back pressure is why it bogged and dies? Ive got the prop up enough where it seems to run the best. The prop is out of the water some. And I thought the same thing about the airbox and have choked it when it messes up on me. It just made it worst

 

[ranger1850v]

Re: johnson 200 compression

And you was right about the cowbell. Haha