fastwin still overheating

This may very well be a stupid question but I'm a goofy guy so here goes. Would a motor running on one cyl. cause an overheating situation? I've done everything I can think of with this motor. I've replaced the impeller the housing looks impecable the thermostat has been replaced I've taken the head off and cleaned all internal ports. I need some help I can't figure it out. Thanks guys. Btw I think one of my new coils aee bad I have a pretty bad miss at idle anything higher it sounds good.

Frustrating....

You are sure the beast is pumping water... the thermostat is functioning...

is it exhausting correctly?

As to the single cylinder causing overheating, I do not know for certain but I would guess no. Have you pulled the spark plug wires while running to isolate/determine if there is a non-functioning cylinder.

What type of overheating are you experiencing? Is the head getting burning hot? Are you shooting steam out the tell tell / pisser?
Is it possible that the heat issue would go away if the motor were moving, like on the lake, as opposed to being tank tested?

She's pumping water I pulled the thermostat housing and it had water just flowing like a water hose. Engine stayed cool then. Put the cover on and she warmed up again.like its not flowing freely inside the block. I ordered anoyher headgasket I'm gonna pull the head after the fair this weekend. Also I'm gonna run it at the lake and see if that helps

Take the thermostat out and put the cover back on and try it. If it still get hot then its got a blockage somewhere but if it dont get hot then I bet the thermostat is bad even if its new doesnt mean its good. Or check it by hanging it in a pan of warm water with the thermometer. Not sure on the temp that it should open at thinking its 145 degrees.

Steve

[url=https://www.tinboats.net/forum/viewtopic.php?p=330667#p330667 said:

acwd » 28 Sep 2013, 07:34[/url]"]Take the thermostat out and put the cover back on and try it. If it still get hot then its got a blockage somewhere but if it dont get hot then I bet the thermostat is bad even if its new doesnt mean its good. Or check it by hanging it in a pan of warm water with the thermometer. Not sure on the temp that it should open at thinking its 145 degrees.

Steve

Click to expand...

good call.

well it quit raining for a while today so i started back on the 66 i have and pulled the flywheel to re do the coils and all since i thought it wouldbe about time. took it all apart put it back together and took her to the drum for a test run. pulled her a few times and nothing so i figured i messed up pulled the flywheel off to find what i call the cam split in half. oops so as for now shes on hold

Well it looks like this motor will be on the back burner till I can find a cam for it. No new parts and nothing on ebay yet. I'm guessing I still need the cam even if I switch to electronic ignition correct?

you telling us you don't have any superglue? :lol:

Do you know the part number of the cam? I was looking the other day and saw several available, but I am not sure it is the correct one for your application.

Not off hand. I thought about brazing the top and bottom of the cracks and see if she holds

braze it up and smooth it down on the outside. got nothing to lose.

Steve

Gonna try if I can get a few min at work tomorrow.

so im guessing the overheating problem cant get figured out till ya get a new cam??? one thing you will notice if and when you pull out the thermostat and run it without it is the motors not gonna wanna idle as smooth as it should, without the stat in there the motors never gonna get up to its proper temp operating range. idling youll notice it but at WOT(wide open throttle) and even just putting around at 1/4 throttle it will/should run fine....

did you check the impeller? make sure the impeller keys not damaged or missing. if damaged or missing your shaft will still spin it and keep water flowing just not the volume it needs to keep the motor cool...

I may have missed this, but for the Miss in the lower cylinder, did you look at the Reeds for the lower cylinder?

At some time, maybe some part of an old impeller was driven through the block, from somebody using the 'ears' at full blast. That will drive the old impeller pieces way up into the block in places you can't reach.
That very likely to the situation you have now.

Your "running on one cylinder" may be evident in your photos and not talking about the broken cam.
Look at the placement of the green or primary wire. Was rubbing against the cam and crank. Looks like it rubbed through.
While looking for the overheat pull the exhaust cover. Inside, on the block side near the top corner (if memory serves me correct), is a hole that should go through to behind the cylinder head. Check and clean out this hole as well as remove all the built up scale in the passages. If you need to, drill the hole back out. Use whatever sized drill bit that is the closest to the original diameter.

Is it possible to get the Head Gasket on wrong?
Maybe covering a water passage?

The green wire got pulled down when the cam came apart. I have yet to pull the reed box due to the fact I can't find a cam.

go to https://www.aomci.org for the cam
ask-a-member section.... you should have one in no time. Also look in the webvertise section for any of those being parted out.
If you have/had a broken reed you can clearly hear the air being forced out and back through the carb. The engine will be doing that or backfiring through the carb. If it ran well above an idle the reed is not broken. I have not gone back through all these posts to see what you have and have not done.
Not a lot of work to pull the intake but............ do whatever you want................

Runs fine just overheating. Head gasket was not sealed well and got water in the bottom cyl. Thanks for the tip on finding the part. I've found a few other fastwins around on craigslist but been too busy with work to snag em yet.