Topic: 54′ 10 hp Johnson overheat – Antique Outboard Motor Club,Inc

This topic has 13 replies, 6 voices, and was last updated 4 years, 4 months ago by frankr.

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November 30, 2019 at 9:56 pm #188331
Geer Pyron
Participant
Yozers,
Hope all you guys had at least okay Thanksgivings.
My nephews were in town and we ran old motors on old substrates (66′ fastwin 18 hp on a 16′ wolverine and a 54′ 10 hp seahorse on a 12′ Meyers) we had a blast!
Till the 10 hp seahorse stopped working.
It slowed and stopped w/in a few seconds while running at wot.
I opened the cowl. Smoke and stink.
I didn’t try to start it again.
The mile tow back to the ramp was fun.
So tonight I couldn’t stand not knowing and so opened it up.
Dropped gearcase.
Green whipped cream all over the outside of the water pump.
Inside of the water pump was wet with water and looked really good.
Gear case lube was good.
Took the power head off.
Some oil in the cavities around front half, around the drive shaft, but not a lot.
Any suggestions?
I’ve run this motor a lot.
It’s my third most favorite.
Oh yea, I took the head off too.
I’m a novice, but it all looked good in both cylinders.
Oh yea, the cylinder head has some scorching on the top, top cylinder, And when I took the lower plug out, the thread repair thingy came out with the plug, and it’s obviously too long. The end of the spark plug is up in the tread repair thing. Long than the threads in the head in other words.
What do you think?
Thanks,
G

JMGP
December 1, 2019 at 4:17 am #188345
frankr
Participant
US Member
So the question has to be Why did it overheat? Obviously, smoke and stink is not normal. Has to be a reason. Can’t tell from here.

But don’t worry about the oily emulsified mess in the exhaust. At least it proves it was not a lack of oil that caused it to quit.
December 1, 2019 at 9:23 am #188352
squierka39
Participant
US Member
Could something have clogged the water inlet? It’s possible to have been covered by something then on the tow home it in covered itself. Or have you tried to blow thru the water lines and see if they are clear? If the impeller is good then something else had to stop the flow of water.
December 1, 2019 at 10:40 am #188357
Geer Pyron
Participant
Yes.
Something could have been blocking the water inlet.
And, as l long as that pistachio flavored whipped cream all over the water pump means nothing, that’s what it had to be.
And, that suggestions jarred my memory. Right after the motor died, in the middle of the 500 acre lake, I did see a clump of hydrilla drifting away from the back of the substrate (boat).
I suspect we picked it up while idling through the shallow canal connecting the two lakes.
Okay. Assuming that was the cause, is there anything I can or should do to the motor to mitigate any damage that my have occurred?
My nature, which I fight with, is to always assume the worst, as in when I got home and told my wife that I destroyed my fifth most favorite motor.
I’m gonna put it back together and run the hell out of just to teach my nature a lesson.
Thanks,
Geer

JMGP
December 1, 2019 at 12:32 pm #188364
frankr
Participant
US Member
For you guys “Up North” that don’t know what Hydrilla is.
December 1, 2019 at 12:57 pm #188370
crosbyman
Participant
Canada Member - 2 Years
I think you should fix that Heli-coil insert for one of proper size which does not extend into the cylinder (mine was about 5/16 no more )

it should line up with the plug base. clean the threads of any oily deposit, reinstall properly with red locktite , punch it in with the punch tool

I would wait a few hours then install that sparkplug

Joining AOMCI has priviledges 🙂
December 1, 2019 at 1:00 pm #188371
crosbyman
Participant
Canada Member - 2 Years
we have those floating around…. came up via the Mississipi rive or down the Niagara river 🙂

waiting for flying carps to show up 🙁

Joining AOMCI has priviledges 🙂
December 1, 2019 at 1:16 pm #188374
fleetwin
Participant
US Member - 2 Years
crosbyman wrote:

I think you should fix that Heli-coil insert for one of proper size which does not extend into the cylinder (mine was about 5/16 no more )

it should line up with the plug base. clean the threads of any oily deposit, reinstall properly with red locktite , punch it in with the punch tool

I would wait a few hours then install that sparkplug

I agree…That exposed helicoil could turn into a hot spot and lead to preignition damage. I’m guessing the crap in the water plugged your cooling passages also. But, I would surely inspect the impeller housing closely, and replace it it is gouged/grooved excessively. I would certainly replace the impeller with an OEM new one also…
Hmmm, one other possibility…..Perhaps the impeller has spun on its metal (or plastic) hub. So, the hub may have been spinning, but the rubber impeller was not….Have a close look at where the rubber bonds to the hub for separattion…
You have the head off, any signs of scuffing/scoring on the cylinder walls? Probably not, these engines are pretty robust and can take a beating. If you are really concerned, you may want to pull off the intake bypass covers which will expose the intake side of the pistons…I do NOT recommend pulling off the exhaust cover, that is a big and messy job.
Once you have determined everything seems OK internally, you may want to give the cylinders a 50 cent hone job with a fine piece of emery/crocus cloth….Sure, not very professional, but we are not dealing with tight tolerances or jet engines parts here…Rough up the cylinders, then clean out any dust with spray ignition cleaner, be sure to oil the cylinder walls liberally afterwards. Did the head gasket appear to be “blown”? Replace it even it it “looks OK”. Be sure to check the cylinder deck and head for flatness…These parts are aluminum and easily distorted during an overheat. I’m guessing this great old QD will be purring again for next season.
One more thing…You mentioned green oily residue, which usually is “normal”. But, be sure to change the gear lube and check for water….No sense reinstalling a leaky gearcase…
- This reply was modified 4 years, 4 months ago by fleetwin.
December 1, 2019 at 9:28 pm #188395
Buccaneer
Participant
US Member
frankr wrote:

For you guys “Up North” that don’t know what Hydrilla is.

Looks like the world turned “PINK”!
Mary Kay would love it, lol.

Prepare to be boarded!
December 1, 2019 at 11:12 pm #188401
Geer Pyron
Participant
Hey y’all.
All is well.
No seriously.
Followed all the above advice, except for replacing the head gasket. And the fity cent hone. I deemed the walls fine and the head gasket too.
I re-did this motor a few months ago, including head gasket and omc impeller. Impeller was still new looking as were the housing and wear plate. Well, the housing is the original one so it’s not perfect, but perfectly acceptable.
I could still see my fity cent hone from back then. I have no excuse for the helicoil. One was flush with the port, the other was….not.
I did run the head over some 220 on my great grandmothers marble breadboard (yes, it is very flat) and got all surfaces shiny.
Put it all back together and it ran well in the barrel. Perfect actually. Started and ran on second pull.
I’m happy.
Yes, hydrilla. I feel like a fool. Ha!
I’ve been fishing in these lakes, including the lake in the above picture since 1990! And I freak over a little weed?
Any hoo thanks for all the input and the take away is…
Start with the simplest thing.
Geer
PS I tried posting a video of me and Py cruising around on the lake the day of the weed but it’s too big and I don’t know how to edit it down to a smaller size.
It’s really funny so I’ll get my daughter to do it tomorrow.
G

JMGP
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