QD-20 compression.

[elgin2]

What is the exceptable compression for a Johnson QD-20 10 h.p.? I picked one up that has 60-65 lbs. compression. Thanx in advance.

[Bob Wight]

My QD-20 runs great with about 82 psi in both cylinders.    Yours might be a little low due to stuck rings or maybe a blown head gasket.

Bob

1937 Champion D2C Deluxe Lite Twin
1954 Johnson CD-11
1955 Johnson QD-16
1957 Evinrude Fastwin 18
1957 Evinrude 3022
1958 Johnson QD-19
1958 Johnson FD-12
1959 Johnson QD-20

“Every 20 minute job is only a broken bolt away from a 3-day project.”
"Every time you remove a broken or seized bolt an angel gets his wings."

[crosbyman]

just run it for a while with some  engine cleaner product .   some like SEAFOAM  some don’t like it  but give it a try. Mercury  and Evinrude have their brand

 

retest after  a few hours … if it runs good maybe your  meter was off …. try another  one and compare

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• This reply was modified 3 years, 3 months ago by crosbyman.

[fleetwin]

I’m not quite sure what year a QD20 is, but you may also want to check for sloppy wrist pin bushings as well.

[elgin2]

Thanx gentlemen. I won’t give up on it then.

[crosbyman]

1959 Johnson QD-20 10hp

Joining AOMCI has priviledges 🙂

[Mumbles]

Compression numbers would be good closer to 100 PSI.

Your ’59 QD-20 should look like this one, with a single chrome ring on top of the hood.

• This reply was modified 3 years, 3 months ago by Mumbles.
• This reply was modified 3 years, 3 months ago by Mumbles.

[elgin2]

That’s it. Got it at a auction for $2.

[crosbyman]

ok we  want a picture or 2 or 3 ….!

Joining AOMCI has priviledges 🙂

[elgin2]

It doesn`t look as nice as the one above. Let me see if i can figure out how to post pictures.

[Author]

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