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Tgtack

Help to figure out HT55C engine code

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Posted (edited)

This is probably pretty simple for the right person, does anyone know what the "T" indicates for Tecumseh engine model HT55c.

 

Thanks.

Edited by Tgtack

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Can't find anything in the Tecumseh manuals so was starting to think it was possibly a typo way back when and then found it in a generic service manual but no explanation and there are many with a T.

Garry

Tecumseh H20-HH70 SM SS.jpg

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Does it have a ring gear on the flywheel?

Maybe it indicates pull start only :confusion-shrug:

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Posted (edited)

High Torque ? 

 

On second thought , that won't work 'cause the rest of them would just be "high" :angry-nono:

 

 

 

 

 

 

 

Edited by Digger 66

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Just guessing,  but it may indicate tapered crankshaft.

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The HT55C was used on the 552 tractors. They were engine forward, horizontal shaft, electric start, aluminum block. That is all that I know about them, and they did not have the recoil starter on them like the earlier H55B/C/D engines.

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Posted (edited)

I have one comming to use on my 551 tractor. I am going to have to duplicate the flat cast mounting base used on the H55D engines rather than the stamped steel mount used on the HT55C engine. The current owner is converting his 552 into a 702.

523229111.jpg

523229118.jpg

Edited by Tgtack

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I also have an HT55C here.Physically the only difference is the cast base. The stamped base sits 1/2" higher. I will check mine tomorrow but I don't think that 1/2" makes a difference. It would only make a difference on top at spark plug clearance to hood, but I don't think it is that close. I will check. As for the belt guard it should work since distance from transmission pulley to engine pulley should be the same. Guard attaches to engine in front so it will just pivot on rear screw and go higher in front.

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8 hours ago, formariz said:

I also have an HT55C here.Physically the only difference is the cast base. The stamped base sits 1/2" higher. I will check mine tomorrow but I don't think that 1/2" makes a difference. It would only make a difference on top at spark plug clearance to hood, but I don't think it is that close. I will check. As for the belt guard it should work since distance from transmission pulley to engine pulley should be the same. Guard attaches to engine in front so it will just pivot on rear screw and go higher in front.

Please check. The initial dimensions I was given was 13 1/4" in height to the tallest cylinder head bolt. The measurement I took from frame to base of hood, was 13 1/4". With the stamped base, it will likely touch the hood.

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Posted (edited)

You are going to be OK with that engine.

Here are precise dimensions based on what I have here:

 

HT55C is 12-5/8" to head bolts/ a long spark plug will add another 1-1/2".

H55D is 12-1/4" to head bolts/top of spark plug to hood is1-1/2" .

There is only 3/8" difference from one engine to another. Even if one is concerned about spark "flying" to hood a spark plug boot can be added. Original does not have boot.

 

The 551 is in my experience the hardest wheel horse to work on and maintain since it is really cramped under that hood and there is a lot of stuff under there.Here are a few  suggestions that I have learned over many years of using one to make servicing it easier;

 

1-Make sure that the steering wheel is easy to remove. I use an easily removable hardened pin. Hood needs to be easy removable to have good access to all under there specially if one has to remove carburetor.A stuck steering wheel makes it hard. Working on it with only a partially raised dangling  hood is absolutely miserable.

 

2- The correct carburetor is very important. It is the Walbro LMG 157. If you don't have it not an easy one to find. It is the only LMG that has all the adjustments on the right side looking at it straight ahead mounted on the tractor . All others have it on the opposite side which is exhaust side. One cannot get to idle mixture adjustment without removing heat shield and even then it is obstructed by the exhaust. Also use the "slotted" hex head bolts for it, since a socket will not fit in there and the open end wrench only turns 1/8' or less specially on left side bolt.Slotted bolts allow to quickly remove or insert them. Also make sure bowl does not leak. All fuel will leak directly on top of battery.

 

3-Devise a quick easy way to disconnect the battery ground at frame mounting point. With everything in place there is no real access to battery terminals to disconnect it. Everything on that tractor is switched by a ground. Very easy to activate starter specially when removing ignition switch cover to access it or spark plug.

 

4- Throttle cable routing is critical for smooth operation. Needs to have long loop not a short sharp one.

 

5-Reinstallation of air cleaner is  very difficult.  It is nearly impossible to find hole at carburetor bracket with the long screw inserted through air cleaner. Instead use a long stud fixed to carburetor bracket and a wing nut at filter.

 

6-If you are going to use it to work for extended periods of time you definitely need to devise a better way to redirect the hot air coming from cylinder head from burning your right leg. Not difficult but a must. I have my right leg at the knee area permanently marked from it.

Edited by formariz
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