1972 6HP Johnrude Bad Head gasket

[G3Joe]

All,

I was working on this motor, a 1972 Johnson 6 hp, for a co-worker, it belonged to his father. It has very light use and is in almost pristine shape. I'm posting on here so that others may learn from my mistakes.

The lesson being that you should alway do a compression check first.

Upon initial inspection I had seen that the carb had a wasp nest in one of the front holes, now, sure the pull starter needed a little work, but after the carb job, getting the pull starter fixed and a timing tweak, I still should have checked the compression.

but instead I went for a test launch.

It would start fine and idle ok, well, maybe a little rough, but I checked the spark on both plugs, bright blue! So on the jon boat it went.

Well wouldn't you know it. It just wouldn't plane out. I mean, when it was in neutral, well it would rev up like a scalded dog. But in gear when it was on the water? Ha, it just wouldn't rev. Just sat in the water and bogged down.

So I went back to the dock, restarted it, and pulled the top wire off. Of course it shut off. uh oh...then restarted again, pulled off the bottom plug wire, ran the same.
(remember I said the idle seemed a little rough? )

Sigh, live and learn. Bottom cylinder had a leaky head gasket-

 

[Tim Frank]

Re: 1972 6HP Johnrude Bad Head gasket

This would be better attached to your original thread so that it makes sense.

 

[levi_tsk]

Re: 1972 6HP Johnrude Bad Head gasket

you can clean the head up with a sheet sand paper spray glued to a piece of glass use 80 grit and figure 8 motions checking fequently, and once everythings shined up nicely all around the sealing surface your done dont get carried away sanding it just until its shiny on all the sealing surfaces..... a head gasket should only be about 20 bux.... and the head gasket should make up any difference in the cylinder surface but you can check that with a feeler gauge and the other side of your glass plate
looks like the head bolts came out ok and thats all the battle on this one
you got lucky on that front - that or you poposess skills ive not learned yet

 

[G3Joe]

Re: 1972 6HP Johnrude Bad Head gasket

Levi

Thanks man...yeah, I did a 4 hp Johnson for a relative last year, one of the head bolts broke off. I had a devil of a time with it, I ended up using a torch, dry ice, (trick I learned from a very smart college buddy while working on an Isuzu) and some PB blaster. Soak it in PB for a few hours, carefully heat up the block, then after drilling a hole in the dry ice, put it on the busted off bolt, of course, I was lucky on that one that it was the head that broke off.

Tim,

I've learned a lot using the search function of this forum. That's why I sometimes post things the way I do. Just kinda telling the story when I'm done at the end of the night in the hopes that someone can learn from my mistakes / solutions, as I have learned from the solutions on here that so many moderators have provided.

So I guess at the end of the day that's what it's all aboot eh?

 

[Tim Frank]

Re: 1972 6HP Johnrude Bad Head gasket

Tim,

I've learned a lot using the search function of this forum. That's why I sometimes post things the way I do. Just kinda telling the story when I'm done at the end of the night in the hopes that someone can learn from my mistakes / solutions, as I have learned from the solutions on here that so many moderators have provided.

So I guess at the end of the day that's what it's all aboot eh?

What was it that Maxwell Smart used to say?..."Sorry about that Chief!".

I thought this was a continuation of another thread featuring a wasp nest in the carb... http://forums.iboats.com/showthread.php?t=477175
Guess it's a big year for wasps.

My point was meant to be that it would have been better to keep it all together....guess I should try to GET it together...

Sorry about that Chief...:facepalm: