M18 Overheated

[ol'George]

easy on the Ether it is not good.
Use a squirt of gasoline instead.
comp is low but further investigation is warranted.
swap in a set of known good plugs and try the starter again later.
If she is been sitting some years, might be other things at play here.
Wouldn't hurt to shoot a squirt of engine oil in the plug holes just as some "pre-lube" as might have some minor rust going on in the Cylinders and/or valves and roll it over a few rounds.
then try to start it again.
might even go straight to the starter terminal with the +jumper cable but leave the ignition Switch on so it can try to start.
Do keep the throttle low and the brake peddle locked down for safety.
They like 1/4 throttle, not wide open.
Obviously you have spark or it would of not tried to start.

[Bryan S]

Originally Posted by ol'George

I honestly don't think he actually overheated it, I think it was maybe hot, but something else gave up that stalled it.

Here's what I'm thinking. So after looking at the plug, I can see it got HOT and the normal build up on the ceramic part
of the plug had flaked off, put new plugs in. My guess is that it was never taken apart since it was put together new, probably lots of carbon
build up over the years, 865 hrs. My thinking is that maybe on the left cylinder, the heat caused a chunk/piece of carbon to break loose and
maybe get stuck in the exhaust valve seat or? It tries to run, with some gas spilled down the hole, but it's acting more like a smoker
than a gasser? So Carb or fuel filer is clogged as well.

[ol'George]

Originally Posted by Bryan S

Here's what I'm thinking. So after looking at the plug, I can see it got HOT and the normal build up on the ceramic part
of the plug had flaked off, put new plugs in. My guess is that it was never taken apart since it was put together new, probably lots of carbon
build up over the years, 865 hrs. My thinking is that maybe on the left cylinder, the heat caused a chunk/piece of carbon to break loose and
maybe get stuck in the exhaust valve seat or? It tries to run, with some gas spilled down the hole, but it's acting more like a smoker
than a gasser? So Carb or fuel filer is clogged as well.

That is a given but we both know an engine will run with the carb sitting on the bench if you dribble a little stream of fuel into the intake. BTDT.
I'd like to see it run some, before we condemn the engine to a bad set of rings or valves.
800 hours is not high hours, yes he said it got hot, I accept that, but I'm a doubting Thomas type of fellow, I need more than someone's opinion.
Now someone I know that is knowledgeable, is a different story.
Just keep playing and if you can keep it running on dribbled fuel, then clean the fuel system.
Hell this is a fun project no worries just yet.
The tank prolly is a mess inside as far as old fuel/crud as is the carb bowl.
Maybe the fuel pump needs attention also.
Start at the tank checking flow and correct accordingly as you move toward the carb.

[Bryan S]

No, not condemning the motor at all. Yes it has some issues (so do I), but also shows signs of life. I put about a TBS of Marvel down each hole,
put the plugs back in and cranked it over for about 5 seconds, closed the hood and let er sit. Marvel can do what it can overnight.
The temps are dropping faster than the sun behind the horizon. Going down to mid 20's tonight, tomorrow's another day. I like to tinker,
but also like to be able to feel my fingers.
Thanks for all the help.

[ol'George]

Originally Posted by Bryan S

No, not condemning the motor at all. Yes it has some issues (so do I), but also shows signs of life. I put about a TBS of Marvel down each hole,
put the plugs back in and cranked it over for about 5 seconds, closed the hood and let er sit. Marvel can do what it can overnight.
The temps are dropping faster than the sun behind the horizon. Going down to mid 20's tonight, tomorrow's another day. I like to tinker,
but also like to be able to feel my fingers.
Thanks for all the help.

Always enjoy helping, it is rewarding especially when it turns out well, and
all reading learn something,

What is not to like about that?

Besides the man up stairs adds another virgin to my list on Venus for every person I help
(and forever is a long time and I wouldn't want to run out early on)