What should I look for in my HT Engine after Teardown? Previous RPM problems

[StrontiumEthics]

Ok, well I successfully took apart my HT engine, All bearings, Seals, and parts generally seem to be intact. Previously, the problem I had was that my engine did not Idle but kept revving when I started it. I adjusted the carburetor to the best of my ability and even switched it with a spare one I had several time. I also switched the throttle cable, and check the barrel slide in the carb. But no good. Finally I decided to tear this engine down. And not I did. = )

 

[Al.Fisherman]

The only thing I can think of is either a cylinder base gasket or the case gasket. Either can leak and suck in air.

 

[AussieSteve]

How old is your engine? If it's not new, I'd recommend replacing the crankshaft seals even if they look OK, while you've got the chance.

Clean up the mating surfaces of the crankcase halves, so that they'll seal well. (Wet & Dry paper on a sheet of flat glass is a good way to do this.) Don't remove a lot of material.

Do the same to the head and other mating surfaces, including the inlet tube and exhaust.

For the crankcase, buy some oil jointing paper and cut a new gasket, unless you can buy one.

Do the same with the inlet-to-barrel gasket.

Buy new base, head and exhaust gaskets.

It sounded like a carb-related problem from the start, but you ruled that out by swapping for another working carb without improving things, so hopefully a careful rebuild will do the trick.

Ron, you posted while I was typing. Doesn't matter. We're speaking the same language.

 

[StrontiumEthics]

I am having a problem installing the bottom end of the crank case. For some reason, when I connect to 2 pieces and put gasket in between there is still some extra space. and when I try to tighten the screws on the crankcase the crankshaft gets a little stiff. What can be the problem?

 

[210061741]

My guess is the seal lip is hanging up on the crankshaft.
Need to make sure the bearings are seated all the way and check that the inner lip of the seal isn't being pushed out by the crankshaft

 

[StrontiumEthics]

I think that the bearing aren't all the way in. like a millimeter is poking out. But i cant seem to get it in even when pounding it hard. What can I do?

 

[210061741]

The mainbearings will sit not quite flush.

Check the seals and align the cases.

 

[StrontiumEthics]

Ohh that's why. I thought the bearings were suppose to sit right inside. Just like a millimeter is poking out. But i hammered them on a wooden block and then alligned the cases and even screwed in some of the bolts but there still is extra space It also gives a hard time screwing in and when I start screwing one side the other side lifts up a little.

 

[210061741]

Here is what i would try.

Put the crankshaft and the clutch shaft in 1 case half.

Slide the other case half on and pay attention to the seals.
The lip is going to want to push out as the crank goes in.

Carefully use something to push the seal lip back in.
Im talking about the lip around the shaft.

If that lip did push out you could have got the spring off the seal jammed between the bearing and the seal which would cause you problems.

Did you replace the seals.

I would pop them out and put the bottom end together without the seals.

Than when you got it together put new seals in.

also when you got the cases together put all the case screws in loose.

Then put the cylinder and head on and bolt them down tight.

that will pull the cases to the cylinder and should line it up pretty good.

Then tighten all the case screws.

The crank should turn pretty easy.

My best guess is the spring on the seal came off and is jammed in there.

Take the crank out and very carefully pry up the inside lip of the seal and check to see if the spring is on.

 

[StrontiumEthics]

Oh. I did not mention that all this time I was putting the bottom end together WITHOUT the seals...there was still room.