Tecumseu

Harry Keller · Jun 27, 2016

Hope I am on the right forummMy tecumseu fomula 13.5 hp starts right up and mows gras but when I shut it off when warm it will not start up unless I choke it..Just need to choke it for acouple cranks and it is away...Now thinking it was the carb I installed a new one to no avail as it works the same..I just can not figure it out...Does it not have enough vacuum to draw gas when using th starter??It started this foolishness by surging a lot and that led to me cleaning the carb which made it a little better so decided on a new carb...Not much better with new carb than after I cleaned the original..Maybe someone out ther can help?? Harry

johnlobb · Jun 27, 2016

The guys in the garden tractor forum are very helpful.

Steve@Advance · Jun 27, 2016

The surging and hard start are symptoms of being too lean. That is a common problem with the newer motors, especially the ones with no mixture adjustments on the carb.

Too lean can be caused by a vacuum leak. Be sure to eliminate that possibility before proceeding. It can also be caused by dirty or water contaminated fuel. Take a look in the bowl of the new carb, see if there is any sign of contamination. If so, clean it thoroughly, look in the tank, clean it and the filter.

If the carb has mixture adjustments, try enriching the mix by turning then out slightly.

If there are no adjustments, now that you have another carb, you can try some rejetting. This is a somewhat tedious procedure and requires some tiny drill bits. You'll need to locate the main jet, determine the size, then drill it out .001" at a time, trying it at each interval. It won't take much! But you do have a spare to fall back on just in case!

Traper · Jun 27, 2016

Harry Check valve clearance older engines loose intake valve clearance . traper

RogerinIowa · Jun 27, 2016

This engine has a carburetor, NOT fuel injection like your car. It needs fuel to start, hot or cold, that is why you choke it to start it. There is nothing wrong because you have to choke it!

casecollectorsc · Jun 27, 2016

If you shut the engine down when hot, I imagine some of the fuel in the carb. evaporates from the heat.....that is why it needs some choke when restarting. No big deal.

Harry Keller · Jun 27, 2016

OK I realize it does run lean with no adjustments on the carbbutit ran fine and startedgreat until all of a sudden the surging and forgot to mention the spitting back through carb until warmed up.. I will check the valve clearance if possible..As you say no problem just because I have to use the choke to start but this is not the way it should be when warm..The carb replacement at least got rid of the surging and I can mow with it so not a loss..THANKS Harry

steve_in_mo · Jun 28, 2016

Older engines got enough fuel through the carburetor to restart after a warm shutdown. Newer ones "probably" do not.

jimg.allentown · Jun 28, 2016

I have always found that the single cylinder engines in the 5 to 16 horsepower range seem to always need choke to start - warm or cold. I just chalk it up to a quirk of the engine.
Now, the surging or poor running is another matter. I have found that the tiny little passages in those carburetors are somewhat prone to plugging up. A thorough cleaning seems to remedy the problem. I have had to re-clean them more than once to get them right.
Also, the fuels with the ethanol in them do alter the effective mixture requirement. This may cause am engine's mixture to be richer or leaner than ideal.

Tecumseu

Harry Keller

Member

johnlobb

Well-known Member

Steve@Advance

Well-known Member

Traper

Member

RogerinIowa

Member

casecollectorsc

Well-known Member

Harry Keller

Member

steve_in_mo

Well-known Member

jimg.allentown

Well-known Member

Similar threads