1953 johnson 10hp quest.

[jbjennings]

I got myself a "new" '53 10hp. It runs pretty darned nice in a barrel,cranks very easily, has nice power, shifts good, pumps water and stays cool really nice. It also has a new head gasket and brand new head bolts (hmmm?). When I first tested it in a barrel it had a little water leaking between the power head and exhaust tower. I couldn't stand it so decided to pull the power head, make my own gasket and fix it before I ran it. After cleaning all surfaces and remounting it, I noticed that the exhaust tower was not fitting nice and snug. It appeared that the little front section of the mid section where the drive shaft comes through was a hair higher than the exhaust section and this was what was making the faulty seal.. I have no idea why this would be true. I'm thinking that this won't hurt the motor but it annoys me just thinking about it. Anyone have any idea what would be the cause of such a thing and how to fix it?
Thanks,
JBJ

 

[F_R]

Re: 1953 johnson 10hp quest.

Not sure exactly sure of the "why" of it, but as I recall the two gaskets are different thicknesses to compensate for the different heights.

 

[samo_ott]

Re: 1953 johnson 10hp quest.

They always run great in a barrel. Have you tried it on the water yet? And do a compression test to get a baseline for the future...

 

[jbjennings]

Re: 1953 johnson 10hp quest.

F-R,
I am really glad (and astonished) that you take the time to answer all these questions! I had no idea those gaskets were diff. thicknesses. Could I triple the gasket material with a tiny bit of gasket sealer in between and make up the difference? Yes, I'm cheap but willing to do it right. What do you think? I'll test the comp. and post it shortly.
Thanks,
JBJ

 

[jbjennings]

Re: 1953 johnson 10hp quest.

They always run great in a barrel. Have you tried it on the water yet? And do a compression test to get a baseline for the future...

Sam,
The darned thing only had 70 lbs. on both cylinders. I tested my '58 18hp just to be sure and it had 105 lbs on both cylinders. (it runs great) I don't know if 70 is awful, low, or low but o.k.. What do you think?
Thanks,
JBJ

 

[Scaaty]

Re: 1953 johnson 10hp quest.

Sam,
The darned thing only had 70 lbs. on both cylinders. I tested my '58 18hp just to be sure and it had 105 lbs on both cylinders. (it runs great) I don't know if 70 is awful, low, or low but o.k.. What do you think?
Thanks,
JBJ

They will run fine at 70...probably 90 better, but good nuff

 

[jbjennings]

Re: 1953 johnson 10hp quest.

Thanks Scaaty,
Makes me feel a little better. Going to try and fix that gasket tomorrow if time permits and take 'er for a spin. Will post a pic and a top speed.
JBJ

 

[samo_ott]

Re: 1953 johnson 10hp quest.

I wouldn't want to go much lower than 70 but would always still try it... I just got in a '62 10hp with 80 lbs aside and it runs great in the barrel... gotta get it down to the river soon to see if it 'really' runs though!

 

[Chinewalker]

Re: 1953 johnson 10hp quest.

I would do a decarbon on it as a matter of course - may help the compression a bit. They used lots of oil back then, plus they didn't have the cleaner burning burning stuff we used nowadays. They used regular SAE 30 wt., which left lots of chunky, hard carbon inside...
- Scott