97 Johnson 150 used powerhead

[Krichie]

Ran compression on used powerhead got numbers of 90 and rest are 100. These numbers sound low to me. Are they?

 

[Solittle]

Re: 97 Johnson 150 used powerhead

Welcome Kenny - They are not as high as one would like but I wouldn't be concerned. Your compression guage may read on the low side. Might do a thorough decarb and see if that raised them a bit.

 

[Krichie]

Re: 97 Johnson 150 used powerhead

Thanks SoLittle,<br /> Concerned about the low compression, I am thinking about purchasing the powerhead instead of trying to rebuild mine.

 

[Solittle]

Re: 97 Johnson 150 used powerhead

What is wrong with yours?

 

[cowboyup]

Re: 97 Johnson 150 used powerhead

howdy Kennyr,<br /><br />Welcome aboard. First, if you don't already have one, do yourself a favor and purchase an OMC service manual and parts catalog. Do an internet search, pick a vendor and give your model number. I got mine from Ken Cook Co. I'm not sure if they "own" the literature for that model year or not though. Even if you decide not to rebuild, it's a great resource. <br /> Giddy up.

 

[Krichie]

Re: 97 Johnson 150 used powerhead

Don't know what caused it but had number 3 eat the rings and scored the cylinder bad, and number 5 only had 80 psi. All others were 110 to 115. That is why I needed to know what the compression ran on the 150 Fast Strikes. Still thinking about the used powerhead, engine has not been ran in a while, numbers were 90 on one and 100 on all others cold. Would rebuild mine but mechs in my area are talking 3000.

 

[Krichie]

Re: 97 Johnson 150 used powerhead

Thanks okstatefan, do not have a service manual but do have a clymer that covers this engine. Not going to rebuild right now. May take a chance on the used powerhead. I know guages can read different, but numbers are with 10# of each other and numbers were taken cold.

 

[rodbolt]

Re: 97 Johnson 150 used powerhead

on a two stroke warm or cold is rather irrelavent. the numbers just dont change much. most "used" power heads for sale are junk or they would not be for sale.<br /> I rebuild 10 or so a year that people bought cause it ran good on the flusher or they were told it ran good. do a leakdown test instead of a compression test. anything more than 10% indicates to much leakage.<br /> just a humble opinion

 

[jy118lfd]

Re: 97 Johnson 150 used powerhead

Leakdown test is the way to go Compression is affected by head gaskets heads etc. But leakdown tests the ring seal reguardless of all other variables

 

[rodbolt]

Re: 97 Johnson 150 used powerhead

hello<br /> a leakdown will give the overall seal of the cylinder. but its far more accurate than a compression test.

 

[Krichie]

Re: 97 Johnson 150 used powerhead

 

[Krichie]

Re: 97 Johnson 150 used powerhead

Thanks for all your input on the used powerhead,though this powerhead was complete,started,carbs,powerpacks, etc....for 1500.00, I know you get what you pay for. So I quess I should find a rebuilt powerhead, just don't know if I can come up with that kind of money. I would like your input on where to find a good rebuild, I know some do good work and some don't. Thanks Again.