# ever have this issue??? (tecumseh hm80 8hp)



## twofishy4u (Dec 6, 2011)

I got an older deere 826, early 80's I guess. Starts and runs but only under 1/2 throttle. Cleaned carb and rebuilt, same issue, swapped carb with another 8hp that ran perfect, same problem. Compression is 120. Took exhaust and intake off....all clear. Checked all linkages and even swapped them out with another good engine, cleaned points and set to .020. After that it was better for 10 minutes then it started again. Likely ignition issue but what would cause this????


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## Flannelman (Sep 24, 2011)

Interesting I have a Sears 8hp that does something similar but mine will run wot but sometimes requires half choke even thought the carb is squeaky clean. I'd swapped Spark plugs and that didn't make a difference. I wonder if its the condenser. If it came back when the points probably started to get dirty again since it take more energy to push spark with the higher cylinder pressures at wot. I wonder if the condenser is getting weak on mine to......


I was looking your sure its got points? I was looking and its looks like they've had an all in one ignition coil for a bit.


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## HCBPH (Mar 8, 2011)

*Running issues*

Have you checked that the governor linkage is free to move on it's own? I don't have an 8 HP, but do have a 7 & 10. The one had so much crud around the governor linkage it wasn't moving easily which caused it to run rough. I used alot of brake cleaner and got all the junk off and that freed up the governor.
If it's hung up inside the block, that requires disassembly to get to, but I have not had any like that so far.
Another thing is when you did the carb, did you check the 3 little holes in the side of the carb throat to insure they were open? Try a strand of phone wire and see if it will go through those holes, gummed up and they can cause running issues.
Another thing I like to do is use 'water dispersant' on the points etc inside the engine. It displaces any moisture and helps it run better if any snow etc gets into the flywheel cover.


If these are float type carbs with adjustable jets, the one on the bottom of the bowl adjust high speed (initial open 1 turn) and the one in the side is the low to midrange (initial open 1 1/2 turns). Once running, adjust accordingly.

Just some thoughts.


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## Chuck Turman (Dec 6, 2011)

Should have been in classifieds, wrong forum


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## twofishy4u (Dec 6, 2011)

yes it has points, I'm not crazy.
governer is clean
ordered a point and condensor today, condensor thing makes sense IMO. I'd love to check the timing but that requires a special tool or head removal and is complicated.


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## twofishy4u (Dec 6, 2011)

FIXED!!!! I have discovered others have tried to fix this one(including a dealer) also without luck. I changed the point, condensor and plug cap, better but not right and I want it perfect. So I pulled the head got a dial indicator from work and set the timing on the stator and reset the point gap. Runs PERFECT now, cleaned up nice and should sell easily. For the dozens of 8hp tecumsehs I've had in the past few years this was a 1st. Hopefully a last! Not that hard but a little time consuming.


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## HCBPH (Mar 8, 2011)

*Timing the engine*



twofishy4u said:


> So I pulled the head got a dial indicator from work and set the timing on the stator and reset the point gap.


That would be a good one to do a writeup on along with some pictures of how it's done. I'm sure someone will come up against that at some time and that could be a great reference article.


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## twofishy4u (Dec 6, 2011)

I'd guess this issue is pretty rare. I found the spec was .090 BTDC. So I set the piston to that spec with the dial indicator and just set the contact/point to open then. Then turned the motor so the point was fully open reset the point gap and rechecked the timing again, did this a couple times to get it perfect and it worked well, reason for rechecking is everytime you adjust timing or gap it effects the other, only slightly but it does. Like I said this was at a dealer 1st, I got the unit cheap cause it didn't run well.


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