Topic: 1956 Johnson 10HO QD 19 exhaust housing temp – Page 2

This topic has 50 replies, 11 voices, and was last updated 8 years, 3 months ago by bob-d.

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June 25, 2017 at 9:22 pm #60322
chris-p
Participant
I just went down and inspected an exhaust housing tower I had in the basement.

Not sure how the hot exhaust is getting to the front of the housing. The front has the enclosed drive shaft tube. Did you re install the plastic spacer when you did the water pump with an o ring on either side?

Wondering what baffle plate if any you have installed. There were some changes to that model done. Does you model number have a letter suffix after it?
June 25, 2017 at 9:46 pm #60330
bob-d
Participant
US Member
Pulled head. Found lots of carbon. Sorry the gasket ripped when the head came off. If it would have stayed in one piece maybe would have helped with the detective work. I didnt see part #2 plate? Could that be causing the exhaust to burn the housing, or just a bad gasket?
June 25, 2017 at 9:56 pm #60332
bob-d
Participant
US Member
I now see part number 2 (plate) it was covered with carbon.
June 25, 2017 at 10:03 pm #60333
chris-p
Participant
So did you install the plastic spacer PN# 305304 when you dropped the gearcase? Had an o ring either side?
June 25, 2017 at 10:56 pm #60338
bob-d
Participant
US Member
Yes Chris, I even install two new o rings. I believe they were two different sizes.
June 26, 2017 at 12:05 am #60348
frankr
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I’m thinking there should be a small spray hole somewhere to spray cooling water into the exhaust. But I’m not intimate enough with that model to know where to look.
June 26, 2017 at 12:50 am #60353
bob-d
Participant
US Member
Good point Frank. Will dig around. Checked all cooling passages, tubes etc with compressed air and they all flowed well.
I’m also thinking gasket on exhaust housing under powerhead was shot allowing the hot exhaust gas to move to the front of the housing instead of dumping the exhaust out the back of housing under the pistons?
June 26, 2017 at 5:10 pm #60402
fleetwin
Participant
US Member
Boy, that is cooking, and it doesn’t appear that the engine is overheating….
Have you removed that crazy SS cover with the two screws? Maybe all the carbon has covered ports in there that is causing the hot exhaust to back up…Don’t know what would make it get so hot on the front of the housing though, perhaps the gasket was leaking directing hot exhaust to that area where it was having a hard time escaping….
June 26, 2017 at 8:34 pm #60410
chris-p
Participant
Strange. If the plastic spacer is installed and intact, exhaust gas should not get into that drive shaft tube, unless the gasket was damaged.

There is also a spray hole as Frank stated about half way down, ensure it is not plugged with carbon.
June 26, 2017 at 9:42 pm #60419
jeff-register
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US Member
We had this problem a few years ago with a red J 10hp. Can’t remember the guys name now.
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