Craftsman Snowblower w/ Tecumseh Engine Problem

[FortyCaliber]

KE4AVB...................I will do exactly as you suggested and will report back tomorrow with my results. I did have everything set EXACTLY in this manner, and it would not run, but I will do it again. And I will set the air gap correctly to .0125. Thanks

[KE4AVB]

The IPl indicates that the notch key is correct. As for why they still used the notch key I can't answer as I haven't work on enough Tecumsehes to know the answer. Tecumseh engines were leaving the market when I got into fixing small engines. Several others here definitely have more experience with these than I do.

[Merkava_4]

Yes, that looks pretty darn similar. The number is also the same as the one I just bought.

Then you might check out this note in the link:

"Close-up view of the bowl nut (#6). The larger hole on the side of the nut is the main fuel pickup. The smaller hole is the idle fuel transfer port. The hole within the center of the nut is the main jet. These passages in the bowl nut are the most common source of trouble in the carb. They must be free of debris, gum or varnish."

That Idle passage hole looks pretty small; easy to get clogged up. Also, do you know the correct way to set high speed mixture and low speed mixture? I'm not going to bore you with the long explanation of Air/Fuel mixture if you already know it.

[Merkava_4]

Just another comment: Engines that run too lean to keep a steady RPM are almost ALWAYS caused by fuel contamination clogging up some passageway in the carburetor. Often times the route between the fuel tank and the carburetor is too short to add a fuel filter, especially the tank mounted carburetors, so the carburetor is left at the mercy of the owner to keep the fuel clean.

[38racing]

you say you 'messed' with adjustments. It should start and run with both screws out 1 1/2 turns. Then when running at full speed adjust the needle in bottom of bowl in until it falters and then out until it falters and set at midpoint between the two. Then slow it down as slow as possible with it still running and do the same with the idle mixture screw in the side.

[FortyCaliber]

Hey all. I'm back. I have some "issues" going on with my mother and I wasn't able to work anymore on the snowblower until now.. I read all of the suggestions and comments. I tried getting it to start again but it wouldn't.

Where I'm at now is I took the head off and the breather assembly out. I rotated the flywheel around until I got on the compression stroke. As I was spinning the flywheel, I was checking the seating of the valves. The exhaust valve does NOT seat completely. On any of the strokes, not just the compression stroke, the exhaust valve is not seating fully into its seat. I can wiggle it back and forth a bit. I think I read where they call that "negative lash" or something like that. It is pretty evident that the at least the exhaust valve needs adjusting. I think they both need adjusting. From my understanding there is supposed to be .004 lash between the valve stem and the pushrod on the intake valve, AND .004 - .008 on the exhaust valve?

This is something I have never done, but I'm not afraid to give it a shot. I'm pretty handy. What I need to know, if someone could indulge me, is to how to do it? Just by looking at the valves, it seems that there is a spring and a top and bottom "keeper"on each of them? Do the "keepers" just slide out after the spring is compressed so that the valve(s) can be removed? If that's right, what type of tool is needed to compress the spring?

And once the valve is out, how do I know how much to grind off the stem (since I'm starting with negative clearance)? Is that all there is to it? How do you control the grinding so as not to remove too much material from the stem?

How does the compression release figure into this?

Thanks

[KE4AVB]

First let me say I understand on the problems with your mother. My mother developed serious health issues which taking care of her became a full time job until her death. I had to give up working on anything petty much. I am just now getting back into it full time.

To remove the valves you will need a valve spring compressor and there is several type and styles out there. I use the following tool myself for these l-head engines. This is available as after-market and is available through your local auto part supply stores. There is other versions of removal tools but this one work fairly well on this l-heads as is fairly reasonable cost wise.

First you would position the spring retainer so the larger part of it keyway faces away from you or toward you whichever is easiest for you to remove it later. Here is a picture of what the retainer looks like. This engine use the same type of retainer as the Briggs l--heads.

With the valve in the closed position, you insert the tool it engages as of the spring as possible including the retainer and compress the assembly. Gently work it to disengage the retainer so you can remove the valve. Once the valve is removed you can remove the spring and retainer.

Now to adjust the valve gap you hand file or grind the stem off ever so slightly and check the clearances as you go. It will not take much to do this and it can be easily over done if you get too aggressive about this filing. Just remember that this filing must be keep at 90 degrees of the stem so there will be no high and low spots. For me, I do my adjustment for the exhaust valve when the engine is on the intake stroke (intake valve fully open and exhaust fully closed) as to have compression release out of play. When you get close to final clearance gap you need to reinstall the spring and retainer to fully seat the valve or your gap checks will be off. Yes it is a little time consuming what it takes it to get the clearances right.

Also once you get valve to fully seat it is time check your valve face and seat for pitting and hand grind them using valve grind compound and the suction cup tool for good seating if needed before final gap setting.


I would set the clearance to larger clearance gap in the specs as these will close up over time again; otherwords, if the spec is .004" to .008" then I would use the .008" clearance. It is right opposite on OHV valves as they tend to open up over time.

Once you get things where you want them and after you reinstall the spring and retainer hand cycle the engine a few turns to make sure you have the retainer lock into place. Then you can reassemble the engine.

[FortyCaliber]

OK. I finally was able to work on the motor. I did the valves. I had to grind about .015 off the exhaust valve stem. That produced lash of about .010. I bought some lapping compound and lapped the lash down to about .007. The intake was the opposite problem. The lash was about .011 initially. I lapped that down to about .004. I made a tool for my drill to speed up the process. I bought some industrial velcro and stuck a piece on the top of the valve and another on the tool I made. Worked pretty well. I had to use the screwdriver and zip-tie method to remove the valve springs since I couldn't find a compressor in 5 stores I went to. Napa could have ordered me one for nearly $50, but I couldn't justify it at this time. If I ever do it again, I'll buy a spring compressor.

Checked the head for flatness on a flat piece of glass. It was good. Cleaned up the surface by running it across some fine sandpaper on top of the glass. Cleaned the breather. Cleaned the head mating surface on the block with a fine wire wheel. Bought my gaskets today for reassembly.

The only thing now I have an issue with is I'm not sure which torque sequence to use for the head. In the service manual, the LH195SP isn't mentioned specifically for the head bolt torque. Also, is 200 in-lbs the right torque for the head bolts?

Is there anything else I should or need to do before reassembly?

[rogerf]

Hi,

The Tecumseh flat head manual (which can be down loaded from the downloads section of this forum) shows what seems to be a cylinder head bolt tightening sequence on page 82 (pdf page 85) and the torque settings are shown on page 92 (pdf page 95) of the same document. Yours is an "H" or horizontal model, so the way I read the chart 200 inch pounds is correct, in fact it appears to be correct for all flat head or L Head Tecumseh engines.

If you haven't already downloaded them the Tecumseh 'basic' and 'flat head' pdf files would be a worthwhile download!

Interesting to learn your using snowblowers - we've got +40 degrees C today with high and gusting winds - it's a really bad fire risk day over most of Southern Australia.

Hope you get your machine running properly soon.

Cheers from 'Downunder',
Roger

[KE4AVB]

he only thing now I have an issue with is I'm not sure which torque sequence to use for the head. In the service manual, the LH195SP isn't mentioned specifically for the head bolt torque. Also, is 200 in-lbs the right torque for the head bolts?

Model number conversion (prior 2004)
HSSK55 - LH195SP

Normally you use a three step torquing method to tighten the bolt but in the Tecumseh service manual it says "torque the head bolts in 50 inch pound
increments in the numbered sequence to 200 inch pounds (22.5 Nm)"