Tecumseh engine issue

12 years ago

Hello,
I recently bought a rotavator, it has a Tecumseh Prisma 37 engine. When it came all of the linkages on the throttle were in the wrong place so i changed them according to diagrams on the internet.

The problem i have now is that the engine will not rev at a reasonable speed. Its revs very high and if you close the throttle slightly the revs fall sharply and it stalls. The opposite for increasing the throttle, it rises very quickly to a very high rate.

I have adjusted the limiting screws and seemed to have tried many different set ups all with the same result.

Has anybody else had this problem or does anybody know how to fix it?

Many Thanks

Will

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Comments (6)

loger_gw
12 years ago
1. Please show a good close picture of your linkage setup.
2. A picture or link to the Internet setup.
3. This will give those familiar a view to share what works best for them.
chas045
12 years ago
Is the connection to your governor shaft tightened?
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hippy
12 years ago
Since adjusting the HI and LO limits screws does not help.

Check the throttle "rod" where it attaches to the throttle plate. I have no clue as to the proper name for the parts. But it is the part that the red arrow points to. Where the rod attaches to the plate. The connection is just pressed tight and flared over like a rivet. Wear over time can cause the two parts to separate causing the throttle to go nuts and impossible to adjust correctly.

One way to check and repair the parts is.
Remove the carb.
Hold the throttle plate in the closed inside of the carb.
Try to work the plate on top of the carb and look for any play between the two parts.
If you find excess play. Hold the throttle plate closed in the carb and the plate on top of the carb in the closed position.
Mark the two parts where they should be. AWL works good for this.
Remove the screws that hold the plate inside of the carb and pull the rod out through the top.
Clean the parts good, align the marks and Silver solder using flux the two together. (Turning the two upside down prevents the solder from running down the rod).
Reinstall the throttle plate and the carb to the engine and try again.
baymee
12 years ago
You don't say anywhere that you adjusted the governor arm and stem properly. Did you?
ashtonw25
Original Author
12 years ago
Hello,

Thanks for the replies.
The linkages are in place exactly the same as in the picture.
There is a possibility i have not adjusted the governor arm properly, could you give me any advice on how to do this?

I will look to see if there is wear between the throttle plate and top plate. Thank you for the suggestion.

Kind regards

Will
baymee
12 years ago
If you removed the arm, then you have to readjust the governor. If not, then no.

The arm is on the right of the pic and the springs attach to it. Loosen the screw that tightens the arm to the small shaft that comes out of the engine so that it doesn't turn the shaft.

Tecumseh engines:

Rotate the governor shaft counterclockwise as far as possible on vertical crankshaft engines or clockwise on horizontal crankshaft engines and hold it there. At the same time, move the governor arm until the carb throttle shaft is in the wide open position. Then tighten the governor shaft screw, making sure you held the shaft in the proper position.