Tecumseh HM100-159409P Carb

[mowfixer]

I discovered my running problem after trying three carbs. Third (original works)

I have looked on line for the correct carb and all I can find are Chinese carbs with the wrong fuel inlet. My fuel line goes behind flywheel and connects to a straight pipe on the carb. The replacements have a right angle inlet which I could make work by re routing fuel line. I have 2 Chinese carbs that both quit after motor runs for 20 minutes. These carbs have a metal seat and needle with rubber tip rather than metal needle and viton seat. Something in these carbs are acting up when they get hot. I pulled float bowl and it was full of fuel but motor would not run until engine cooled for 10 minutes. I ran factory carb today for 2 hours and engine runs perfectly but its not in great shape and has too much internal corrosion from bad fuel to be rebuildable but for now it does run.

My question is where can I find a better quality carb. I see even major small engine parts houses are selling these junk carbs. Its sad there are no quality parts available any more.

Thanks

Mowfixer

[KE4AVB]

It sounds like you are getting a fuel pump version of the carburetor in the after markets which would explain the fuel starvation problem.

Appears that you need the 640152A carburetor. Jacks and Partstree both this carburetor listed. But indicate that you receive the straight fuel fitting as a separate item so that would need swapping out.

I did look it up at my distributor and they subbed the Oregon (Silver Streak) 50-655.

[mowfixer]

Yes I saw the Qregon part but on the outside it looks like the 2 Chinese carbs that were listed as a sub for the 640152A. I couldnt believe 2 carbs had the exact same issues. Wish factory carb was not so full of scale and corrosion or I would rebuild it. Its so bad I couldnt get float pin out to look at needle and seat. But it does run in spite of all of that.

Oregon is a bit more costly but hate to get one and have a repeat. Maybe time to unload generator now that its running. I used to do weekend repair at a local small engine shop for years and it was always fun. But we had good quality replacement parts. I dont see how a shop can guarantee work when they have to give customer these poor parts.

Also the idle adjust needle with casp on it had to be adjusted on both replacement carbs to get engine to run. Put spring on them so adjustment would hold.

Thanks

Mowfixer
K4MT

[KE4AVB]

Those are suppose to be a fixed idle mixture.

Clones are usually iffy at the best. And many vendors are just selling will fit version with no guarantee they will work right. They are just hoping they will or the purchaser will give up. Now getting the Tecumseh version is also iffy as they the original Tecumseh company has been out of business for a long time at least since 2009 when I start my repair shop.

[mowfixer]

Yes its sad and its hardly worth making a fuss about a 30 dollar carb that you buy online. So I guess they can sell a lot of bad ones and people just throw them out. For the life of me I can see how a carb will run 20 minutes fine and then start starving for fuel even though float bowl is full of gas. And 2 carbs do the same thing. I remember Oregon sold better quality parts at one time but not sure if they have settled to the bottom like the rest.

I have no choice but to hope I get one that works. I need this 6 KW generator and I got if from a guy who had it sitting in his barn for years. Thats why it has so many issues but with good carb she runs perfectly if I can find one. Until then hope this OEM carb keeps running well.

What do you do in a shop when you cant get good parts? Hard to guarantee a repair.

Thanks

Mowfixer

[Skywatcher]

Hi Mow

In a case where the engine is no longer made or the OEM has gone out of business, you start by telling the customer this fact. Next, you advise him that because OEM parts are NLA, your shop cannot warranty the repair for the simple fact that the aftermarket part manufacturer has no warranty on their parts. Then you let your customer decide whether he or she wants to proceed with the repairs. When a machine gets to be 20 or 30 years old, sometimes even older, it's almost impossible to warranty repairs on equipment that old. An former old co-worker had a saying,

"Sometimes tired iron, is just tired iron."

You tell your customer that you'll do the best you can with what you have to work with and that's the best you can do. Hope this gives you a few ideas,

Sky

[mowfixer]

Yes Sky thats a true statement.

I see a carb that is fully adjustable but for snowblower application. It has 2 differences.

One no connection for breather tube
Has a small tube I believe is for a primer.

I read about some guys who have used this carb. Would you somply plug the primer tube or would it have to be used.

Just a thought.

Generator still running fine on OEM worn out carb but wont run with Chinese replacements.

[bgsengine]

Would you somply plug the primer tube or would it have to be used.
.

Whatever you do ,don't plug it. Had a unit in not all that long ago (I posted about it in the forums here at some point) where whoever worked on it before plugged the primer hose nipple with RTV , presumably to keep dirt out or something.. Problem is, that nipple is the BOWL VENT.. if it is plugged, it depresses the fuel level in the float bowl, and the float won't come up high enough to seat, thus, the engine ends up flooding out and gas running out of the carb, since float can't come up far enough to shut off fuel flow, and fuel will keep flowing up and out through the jets... It does not have to be used (if it is, then it has to have a vented primer attached to it)

[Arkie]

Just couple hints:

I've got a HM100 Tecum Generator engine with the 5 gallon top mounted fuel tank with spare carbs of the 90 degree type and the OEM is straight barb.
What I done so as to change out the carbs easily is on the 90 degree barb I just ran the fuel hose around the carb side of the engine with a red briggs inline fuel filter to the barb.
For the OEM carb with the straight barb I ran a 1/4 inch copper tubing under the air cowling in place of the OEM fuel line and secured good so as to not move around and stubbed out so as when I change carbs in emergency winter use if needed I just connect to the copper tube easily. the ends of the cu tubing is taped/sealed off to keep dirt out. The engines breather hose is connected to the back of the air breather assembly by the carb intake. Most of the HM
100's I've worked on had a very lean carb issue and would surge and hunt if the carb is the low emission type with no adjustments available. On some of the carbs that caused the engine to surge worse I just carefully enriched the L jet slightly with good results. Them clone carbs bowls will rust/corrode really fast when on the engine during storage even with non-ethanol gas.
What I do to keep the carb ready to go before the gen's engine is to be stored for awhile is remove the carb drain bowl stud, drain the bowl and send straight ATF to the bowl through the short section of fuel hose, tag the engine with a note to drain the ATF from the bowl before placing in service. I also drain all the non-ethanol gas and then pour a couple cups of ATF mixed gas into the tank if it's steel tank, slosh it around to prevent rusting/corrosion.
I've also converted some of those HM100's to propane with good results, back when the HM100 was not completed obsolete and could find parts, could switch from propane to gasoline fuel within couple minutes just opening and closing valves. Do not have to be concerned about old gas in the carb, etc, when engines are operated from propane or Nat gas.
If you have access to a USonic cleaner, sometimes them old cruddy/rusty OEM carbs will clean-up good enough to keep using.

Have to really keep a heads up and not invest many $$'s into a vintage obsolete HM100 GENERATOR engine or any Tecumseh engine because parts are expensive if ever found and the generator CRANKSHAFT is a special type, tapered on their gen end, etc and if of the Coleman Powermate types the generator section is also kinda wimpy weak and parts are also NLA unless used. Seems about time very many $$'s are invested is when major stuff breaks/smokes
So playing with a dinosaur egg.

[mowfixer]

Thanks for the tips. I know I am working on an obsolete generator but I have lots of time so dont mind messing with it. I had lots of spare parts left over when I worked part time in a small engine shop and later my own business. The only thing I think would help this motor is a fully adjustable carb and not the EPA carb garbage. I have found snowblower carbs that will work and have a primer for easy starting and are fully adjustable.

Right now the generator is running fine with factory carb but its in bad shape. I have 2 aftermarket carbs that simply will not run right. I have had it running for a few hours in the past few days and its doing fine in spite of carb with badly corroded internals.

I run nothing but non ethanol in all my small engines and dont keep much on hand to go bad as I can get it from a station 5 minutes from here when I need it so I always have fresh fuel. Station sells lots of it and has trouble keeping their tanks full.

I can re-route fuel line simply enough if necessary rather than behind blower housing. Its been a fun project for a guy with nothing better to do who loves working on small engines. Too bad it had to be a POS Tecumseh engine and not a briggs. We rarely have power outages as our electric is underground so if it will run long enough to keep food from going bad in fridge I will be happy.

Thanks all for the advice.

Mowfixer