Tecumseh Horizontal 4.5 hp L head engine surging

GMoore

Forum Newbie
Joined
Mar 11, 2017
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Hi guys,
I know I should post model numbers and I will as soon as I go back out to the shop. The machine was brought to me with very old gas, I mean that nasty green stuff that stinks. Here is what has been done so far. I am out of ideas.
Complete carb cleaning, removed welch plugs, ran wires threw all the air passage ways, followed by compressed air and carb cleaner. new bowl gasket, needle and seat, jet gasket. new welch plugs, idler jet cleaned. flushed the fuel, cleaned the tank, new gas line with inline filter. still surging.
So I tried a second carb, still surging.
Pulled the head, cylinder looks OK, no scoring. re-seated the valves, verified tappit clearance. Still surging.
Checked the crank key for timing advance. it is straight.
Planed the intake manifold surfaces and installed new gaskets, no air leaks. Still surging.
I reset the governor setting.
The motor still surges at all rpms and when cold or hot.
I am out of ideas.:confused2:
 

BlazNT

Lawn Pro
Joined
Apr 26, 2012
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28
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6,973
Air leak after the carb would be where I would start looking.
 

bertsmobile1

Lawn Royalty
Joined
Nov 29, 2014
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64
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24,647
Also worth trying is an alternative fuel tank,
I keep an old Tecumseh tank for big engines and a kawakasi tank for hand helds .
Always a good start with weird running.
If you hold the govenor and slowly increase speed dose the engine respond properly.
If not you have a govenor problem.
 
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