# New Tecumseh HH60 Question: Seized?



## mikeinri (Dec 2, 2009)

Hey guys,

I have an older Troy Bilt Horse tiller, with a Tecumseh HH60 engine. Tiller is circa 1974, shortblock was replaced around 1982-3...

Has newer carb (replaced about 2 years ago) and was running great at that time, but it rarely gets used and has been running poorly as of last year. Had stuff floating in the gas tank, so it probably needs a good carb cleaning.

So, I removed the bowl, cleaned out the main screw, etc. Got it running, but it "hunts" and will only run (poorly) at full throttle, stalls if choke is used after starting.

I (stupidly?) moved the governor linkage, and got it running without hunting. Problem is, I adjusted it so much that I basically took away any affect of the governor.

I then proceeded to adjust the carb main jet (leaner), and got it running very fast and smoothly (air cleaner removed). It was blowing smoke out the breather tube, after a minute or two, it just slowed down and stopped running. No banging or anything, just stopped running. My guess is that I overheated it, and possibly burned up too much oil in the process.

Pull start would not turn, so I assumed it is siezed and beyond hope. 

Someone told me to try Marvel Mystery Oil to unsieze it. I never believe in magic potions, but for $3.00 I figured it's worth a shot.

Well, I put the MMO into the spark plug hole, removed the starter, and was able to get the engine to turn with a 3/4 socket on the nut in front of the engine!!!

So, I am assuming it's not totally scrap yet, and will let the MMO work in for another day or two, then I'll try to fire it up. 

My question is, has anyone else resurrected something like this, and how likely is it that the engine will be back to "normal" just by unsiezing it? I know I will still have to deal with the carb, but if the engine itself is good, that's my main concern at this time.

If all esle fails, I can repower with the el-cheapo Harbor Freight engine, but I really am trying not to have to remove this engine.

Thanks.

Mike


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## mikeinri (Dec 2, 2009)

Quick update:

OK, after letting it sit for about 24 hours with the MMO in the cylinder, I took out the spark plug and noted that the cylinder was empty. Not sure where the MMO went, it's possible it drained out of one of the valves (I have no idea how to know if the engine was set with the valves closed when I left it to soak).

In any event, took my socket wrench, and the engine is turning quite freely now, in both directions. So, I think I'm out of the woods in terms of it being siezed. 

Hopefully, it will still have enough compression to run, and won't burn terrific amounts of oil.

I didn't have much time last night, so I'll change the oil and try to fire it up tonight...

Mike


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## mikeinri (Dec 2, 2009)

Wow, are you sitting down for this???

Spun the engine some more with the socket wrench, changed the oil. Replaced pull starter, spun it some more to lube up with the new oil.

Reset the governor linkage back to where it was originally. Something was bugging me about the carb, so I took out the manual to look up the factory settings for the main jet and idle jet screws. Reset the main jet (I know this was clean since I just cleaned it last week). 

Went to remove and clean the idle jet, but wanted to check the setting first. However, it wouldn't turn in, even with a screwdriver. So, I removed it completely, and it was very clean inside. Cleaned up the outside and spring with carb cleaner, replaced it and reset it to the factory setting.

EUREKA!!! Engine started after a few pulls!!! Smoked for a while (MMO burning out of the exhaust, where it was dripping out after making its way from the chamber out through the exhaust valve).

Now, it purrs like a kitten, runs great at all speeds, and doesn't smoke at all.

Unflipping believable...

I don't think the MMO was as much of a magic fix as total luck. I think I ran the oil dry, which stopped the motor, but not enough to sieze it completely. Once I got it freed up with new oil, I think it was just a matter of setting the carb correctly.

Weird thing is, when I installed this brand new carb two years ago, I never checked either of the adjustment screws, I "assumed" they were set to factory settings at the, I don't know... FACTORY???

At the time, it ran better than the old carb, so I just figured it was an old engine and that was as good as it would get.

This engine now runs better than at any time since I've owned it (4-5 years).

Yikes...

Mike


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## mikeinri (Dec 2, 2009)

Well, it was good while it lasted...

I was tilling some new (unbroken) ground, the tines slowed/stopped, and something in the engine made a clanking sound (not very loud), and the engine stalled.

Engine turns freely with pull starter, and something is clanking in the engine. The crank turns fine (PTO pulleys turn with starter), but it won't even attempt to turn over.

Any chance it's something as simple as a sheared flywheel key? 

I'm very handy and like to fix my own stuff, but I'm not a mechanic and don't have the free time or interest to spend more than a few hours more on this, so if it needs a major teardown, it's going to be sold to someone who can fix it.

Mike


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## Basementgeek (Feb 7, 2005)

Any compression at all ?

Sounds bad. Not key way.

You are going to have to open it up to find out. My guess not worth repairing.

BG


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## 2and4StrokeTech (Apr 6, 2011)

Chances are your rod cap just gave out. Time for a repower.


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## mikeinri (Dec 2, 2009)

Thanks guys, that's along the lines of what I was thinking too...

At least I got the garden tilled before I killed it. 

Too bad, I wish I'd had the time to take a video when it was running well. You guys would appreciate how smoothly a nearly 40 year old engine was running.

Mike


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## Basementgeek (Feb 7, 2005)

Glad you got done what you set out to do.

The are many people that have engines older than yours that are still running, but rebuilding them gets pretty $$$$.

My riding mower is 27 years old, runs strong, but I would not rebuild the engine when it dies.

BG


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