Small engine question again

Zachary Hoyt · Feb 12, 2012

To recap the situation: I bought a new single speed Tecumseh generator engine from Surplus Center and put it in my 18" planer. It ran rough and surged at first and I had to keep the choke on to keep it running. Some folks on here suggested Sea Foam and higher octane gas, and it ran better for a little while. Now it sounds like it is backfiring and it shoots a 2+inch long blue flame out of the exhaust with every pop it makes. It will pop three or four times in a row, then run smoothly for a few seconds, then pop some more. I am not sure what to check next, I understand that the timing is maintained by a key so I think that is maybe not likely the problem. It still seems to like to have the choke on a little bit, so I am wondering if it is still a fuel problem. Any advice will be much appreciated.
Zach

oldtanker · Feb 12, 2012

Pull the flywheel and make sure the key is ok. Even part way sheared will affect the timing. ANd they keys for samll engines are designed to shear to prevent crank damage. I've seen em shear from just the flywheel being loose.

Rick

LJD · Feb 12, 2012

Pull the carb apart. Sounds like it's running way too lean.

I almost bought a couple of those engines. $135 for a brand new cast-iron engine was tempting. Tecumseh model LH358XA-15493

Considering Tecumseh no longer exists, I suspect those engines have been in storage for quite awhile.

Duner Wi · Feb 12, 2012

If it were mine I would make the mixture a bit richer to help the lean condition. Second I would add a wee bit of Marvel Mystery oil to fix what may be a hanging exhaust valve.

El Toro · Feb 12, 2012

If the carburetor has a main jet needle valve you need to open that to enrich the fuel mixture. Hal

VicS · Feb 12, 2012

I have a 10 hp 5000 watt coleman generator which has a Tecumseh engine. It had set for 3 to 5 yrs in the store, but hadn't any gas or oil. I have just ran it twice. It will run just like yours unless the choke is on just a little. I do have ethanol gas. I have did everything short of boring the jet. I just think I will leave the choke on a little. I put a rubber band on it and the 1/2 notch it pulls it is just right. I don't like it but don't know anything else to do. Vic

dixon boy RL · Feb 12, 2012

if it still runs better with choke on some then it is still in the fuel side. first off is this unit gravity fed or fuel pump fed? does it have an inline fuel filter on it.let me know will go from there.

wisbaker · Feb 12, 2012

Maybe we know why Tecumseh is no longer around? They built some really neat stuff that seemed like it should be good but never quite lived up to their potential. 30-35 years ago they had an OHV engine Toro used them on their first riding geeensmowers (GMIII) within 3 years most of them had been retrofitted with a Kohler K321. They also made a line with pressure oiling on the crank, had a little plunger pump in the oil sump, they usually didn't run any longer than a Kool-Bore Briggs & Stratton and no where as long as a Kohler K series.

Bob Bancroft · Feb 12, 2012

When my twin cylinder lawn mower started running lean and needing choke, I blamed it on ethanol. As it got worse, I had to do something. So I pulled the carb. apart. There was a little speck down in the bowl. Cleaned it out and has run great ever since.
I developed a dislike for Tecumsehs when I worked on them. Seems like you had to have them adjusted so rich they smoked black before they would run right.

504 · Feb 12, 2012

The first thing is try a new spark plug. It is a cheap fix if it works, and I have seen a lot of bad plugs do some really strange things.

buickanddeere · Feb 12, 2012

Likely some caps or covers cast, pressed or soldered over the idle and main adjustment screws.
Often just turning them one turn open farther than returning one turn back to the original position as the engine is running. Is enough to knock the dirt and goo loose that was partly blocking flow.

Greenday · Feb 12, 2012

its running to lean!

pat sublett · Feb 12, 2012

I didn't know Tecumseh no longer made engines. I wish that had quit before I quit working on engines. I always hoped they would go broke.

supergrumpy · Feb 12, 2012

I have seen some recent egines with non-adjustable main and idle jets

when they run lean, you have to start running larger and larger number drills thru the jets until they run properly, tedious, thank the EPA

process takes a while and you have to stop before you enlarge the jets too far, usually need to work on both jets

36 Coupe · Feb 12, 2012

Air cleaner may be plugged.Still think running a planer with a gas engine is a bum plan.Tank vent may be plugged too.

UncleTom · Feb 12, 2012

On the bottom of the carb is there an adjustable needle valve or just a hex type bolt? If it has the adjustable needle then open it counter clockwise starting with an 1/8 turn. If has the bolt, take this bolt out. It is actually the main jet. Run a bread tie through the hole. There maybe junk in the bowl also. id bet it is running lean because the jet is partially pluged but there could be other problems as well.

Motorcraftman · Feb 12, 2012

Ya'... And they ALL had the crappiest carbs on them!!!Larry

cole in mo. · Feb 12, 2012

If its a 10 hp, and flat head style, there is a shield covering the carb, remove that, then just above the float bowl, you will see a plastic plug. remove that and there is a jet under it, it will be screwed all the way in. Start the engine and back the screw out about a 1/4 turn, should smooth out and run like silk.

Leroy · Feb 12, 2012

A lot of planers, table saws, drill presses and grinders run with gas engines. Friend gave me the electric motors off the table saw and drill press when he bought them new and uses a gas engine on a line shaft to run everything. Has a remote electric starter on the engine setting just outside his shop in a doghouse type of covering. Gas engine on his well pump as well. But his field sprayer is ground driven.

36 Coupe · Feb 13, 2012

He is using a line shaft so the engine is away from the tool.I have used line shaft power over the years.

oldtanker · Feb 13, 2012

(quoted from post at 15:22:34 02/12/12) I didn't know Tecumseh no longer made engines. I wish that had quit before I quit working on engines. I always hoped they would go broke.

When they went under they tried selling the whole company. Only thing they sold was the tranny division. They just shut the rest down.

Rick

Leroy · Feb 13, 2012

A lot of them are not using the line shaft tho but on individual tools so they can be moved where the ones on the line shaft cannot.

Anonymous-0 · Feb 13, 2012

I don't see many with gunked up carbs doing what you describe, backfiring flame out the exhaust.

Like the other guy said, check your flywheel key.

You may have the exhaust valve either sticking or not seating. The place to start with that is to check the valve clearance. You did not say which model engine, but a lot of the TEC engines run .004 valve lash.

Another thought is your ignition module may be making a spark at the wrong time, when the valve is open.

36 Coupe · Feb 14, 2012

We still dont know if the rig is out doors or not.I ran a small cord wood saw outdoors with a 3 hp Briggs.Had an oil bath air cleaner.A paper air cleaner will clog fast with saw dust.

Small engine question again

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Well-known Member

Similar threads