Big Block Carb issues (H60)--runs rich

[Dr. Shop Teacher]

Got both of my H60s running today (subjects of an earlier thread). Both have brand new H60 knock-off carbs. After running the solid state H60 back about a month and a half ago, I had way too much fuel even with both circuit screws barely open. So, I reset the floats on both carbs to be a bit lower than factory setting.

The solid state engine fired second or third pull (it's the one with the H70 piston). I had to set the idle screw at about 1/4 turn and the main is about 3/4 turn to get it to run at idle. While no longer spitting fuel out the carb, it seems to bog/flood when the throttle is opened.

The points engine took a bit longer to get going, but same issues: idle at 1/4 turn or less and main almost all the way in. It doesn't spit fuel but the plug shows real rich. I could get this one to throttle up and hold though it misfired a couple of times.

Set the float even lower to be open the main some more???? Punt??? I have not installed an air cleaner yet on either engine.

This is the carb: Carburetor for Tecumseh H30 H50 H60 HH60 632230 632272 Engine + Gasket | eBay

My other H60 (on the Trail Bike) has a different carb that does not have the tube on the air cleaner side (I swapped throttle plates to make this one work with the linkage) :
Carburetor W/ Gasket for Tecumseh 631827 632615 632589 632208 H30 H35 H60 | eBay

Suggestions appreciated.:thumbsup:

 

[delray]

hey pete, is there any chance you may have good h big block carb that you could rob off another engine. without really knowing much more about your engines? that might help eliminate if it's a carb issue. it almost sounds like you have a 8 or a 10 hp style carb on it,but i now thats not what you got. over size carb,they will only adjust little bit out and run.

 

[Dr. Shop Teacher]

hey pete, is there any chance you may have good h big block carb that you could rob off another engine. without really knowing much more about your engines? that might help eliminate if it's a carb issue. it almost sounds like you have a 8 or a 10 hp style carb on it,but i now thats not what you got. over size carb,they will only adjust little bit out and run.

You may be onto something. I do, and I will. Thanks, Brian!

 

[control4userguy]

632230 is a 50/60 application. I just ordered a 272 carb for another H60 here so I know that's correct. Honestly, contrary to opinions, I don't mess with $15 carbs. I've run the P/Ns (NOS) you've listed and I was well into the screw travel on the main and a very tight window at around 1-1/4 on the slow...

 

[Dr. Shop Teacher]

632230 is a 50/60 application. I just ordered a 272 carb for another H60 here so I know that's correct. Honestly, contrary to opinions, I don't mess with $15 carbs. I've run the P/Ns (NOS) you've listed and I was well into the screw travel on the main and a very tight window at around 1-1/4 on the slow...

Yeah, I know. A knock off is always a hit or miss. :shrug:

 

[control4userguy]

Not taking a hard line here but it is suspect that you have two engines doing the same thing. You don't say if both were new going on at the same time, immediate problem or after time? Type of fuel used on both?? Cheap gaskets or gasket material not appropriate for fuels containing alcohol is a potential...

Only speaking from my personal experience and my preference is to automatically replace carbs on any used engine I take in with same-supplier units that historically have worked as designed. Anyway, double-check your float levels. That's about all I can think of unless your tanks are mounted on top of a sissy bar. Little reason they should be dumping fuel at that rate.

 

[CLH]

I'm having a HH70 spit gas out the "bowl vent" on the side near the idle speed adjust myself. And I'm using a OEM carb hoping it would have made a difference in quality - I think the OEM carbs are exactly the same as the knock offs, Tecumseh is just now buying them and putting their name on it. A carb cleaning just made the needle seat swell up and caused me to have to replace it. The bowl gasket was dry and crusty compared to the new one in the kit. But even after carb cleaner and blowing out with compressed air, replacement of parts, it is still spitting gas out of the bowl vent on the side. I think the Chinese factory is setting the floats too high on these carburetors and I'm gonna try that next if you say you got it to stop spitting after adjusting the float. I've also have a $15 knock off carb in the mail to see how it'll do.

 

[Dr. Shop Teacher]

Not taking a hard line here but it is suspect that you have two engines doing the same thing. You don't say if both were new going on at the same time, immediate problem or after time? Type of fuel used on both?? Cheap gaskets or gasket material not appropriate for fuels containing alcohol is a potential...

Only speaking from my personal experience and my preference is to automatically replace carbs on any used engine I take in with same-supplier units that historically have worked as designed. Anyway, double-check your float levels. That's about all I can think of unless your tanks are mounted on top of a sissy bar. Little reason they should be dumping fuel at that rate.

Sure is suspect....new vendor for these brand new carbs. Both engines came without carbs, so no OG to try. I used new gaskets and trued the carb adapter surfaces before install. I use 87 octane 10% ethanol. You can't get pure gas here (we are in an emissions testing zone rivaling you guys in SoCal). Problem was immediate and caused me to reset floats lower. No leaks around bowl or main jet. I ordered another carb from a different vendor to try. I also have a small block carb I can swap throttles on. I mount the engines on a workmate to test and use a step ladder to support the test tank just above carb height. I am going to try adding the air cleaner and see if the restriction helps.

I'm having a HH70 spit gas out the "bowl vent" on the side near the idle speed adjust myself. And I'm using a OEM carb hoping it would have made a difference in quality - I think the OEM carbs are exactly the same as the knock offs, Tecumseh is just now buying them and putting their name on it. A carb cleaning just made the needle seat swell up and caused me to have to replace it. The bowl gasket was dry and crusty compared to the new one in the kit. But even after carb cleaner and blowing out with compressed air, replacement of parts, it is still spitting gas out of the bowl vent on the side. I think the Chinese factory is setting the floats too high on these carburetors and I'm gonna try that next if you say you got it to stop spitting after adjusting the float. I've also have a $15 knock off carb in the mail to see how it'll do.

Yeah, I'd set the float lower and see what happens. My "other" H60 needed some adjustment, but came around pretty quickly.

 

[MB165]

The needles should be able to basically shut the fuel off if they are seating properly. float height wont make any difference for this issue, it would have to be overflowing..... is the atmospheric vent for the float chamber present and functioning? if you clamp the fuel hose will they eventually clear up and run properly for a few seconds before running out?

 

[Dr. Shop Teacher]

The needles should be able to basically shut the fuel off if they are seating properly. float height wont make any difference for this issue, it would have to be overflowing..... is the atmospheric vent for the float chamber present and functioning? if you clamp the fuel hose will they eventually clear up and run properly for a few seconds before running out?

Good points. I will check on that. I had similar issues with a small block carb on a OHH195 Tec. At least I'm in no rush on these engines.:laugh:

 

[MB165]

yeah I know about that back burner stuff, im finally dusting off some engines for windber, they have been in shed for 5 years......
clamping that fuel hose is a quick way to verify there is a "rich" condition.
on the points engine, if you run out of things to try to stop the misfires, spitting back through the carb, try closing up the point gap to .018-.019".

 

[CLH]

I ended up saying "fooey" on the OEM Tecumseh carb as it was spitting gas like a sieve directly onto the exhaust pipe, threatening to send my house up in flames. I'm thinking the OEM carb I bought is defective, or has a spider or something that found its way deep inside a passage somewhere from sitting on the shelf in the box for years. I ended up buying a $16 Chinese knock-off one on that I bought off of eBay which I noticed lacked the bowl vent altogether. It solved the issue of spitting gas out the carb, and after some annoying adjustments of the needle seems to run pretty good. At least it isn't spitting gas like a POS now..and it only cost me $16 bucks minus the cost of the defective carb. The stupid and annoying thing is that the main needle on the replacement Chinese carb has to be closed nearly all the way which tells me something isn't quite right, as others mentioned I should be able to kill the engine by seating the needle(s) all the way.

I think it's little finicky problems like, and the quality of their more modern engines (1995 and newer) that earn Tecumseh a bad rep. Little issues like this don't seem to happen as much with Briggs or Honda engines in my experience. Combined with the magneto being UNDER the flywheel, with the head bolts holding down the blower shroud you have to tear a Tecumseh engine damn-near half apart to clean the points, replace a pull rope, or do anything to a Tecumseh. It seems this combined makes working on a Tecumseh an all-day affair generally, at least for me. Nonetheless, I have a lot of respect for these American-made engines. To me it is a DAMN shame that the good OEM replacement parts will one day dry-up and that the aftermarket alternatives aren't worth using, like coils and points from Oregon products are JUNK, and emails to Oregon products complaining about it goes unanswered which makes me want to boycott them vocally. Make working on small engines great again!

 

[Dr. Shop Teacher]

I ended up saying "fooey" on the OEM Tecumseh carb as it was spitting gas like a sieve directly onto the exhaust pipe, threatening to send my house up in flames. I'm thinking the OEM carb I bought is defective, or has a spider or something that found its way deep inside a passage somewhere from sitting on the shelf in the box for years. I ended up buying a $16 Chinese knock-off one on that I bought off of eBay which I noticed lacked the bowl vent altogether. It solved the issue of spitting gas out the carb, and after some annoying adjustments of the needle seems to run pretty good. At least it isn't spitting gas like a POS now..and it only cost me $16 bucks minus the cost of the defective carb. The stupid and annoying thing is that the main needle on the replacement Chinese carb has to be closed nearly all the way which tells me something isn't quite right, as others mentioned I should be able to kill the engine by seating the needle(s) all the way.

I think it's little finicky problems like, and the quality of their more modern engines (1995 and newer) that earn Tecumseh a bad rep. Little issues like this don't seem to happen as much with Briggs or Honda engines in my experience. Combined with the magneto being UNDER the flywheel, with the head bolts holding down the blower shroud you have to tear a Tecumseh engine damn-near half apart to clean the points, replace a pull rope, or do anything to a Tecumseh. It seems this combined makes working on a Tecumseh an all-day affair generally, at least for me. Nonetheless, I have a lot of respect for these American-made engines. To me it is a DAMN shame that the good OEM replacement parts will one day dry-up and that the aftermarket alternatives aren't worth using, like coils and points from Oregon products are JUNK, and emails to Oregon products complaining about it goes unanswered which makes me want to boycott them vocally. Make working on small engines great again!

I'll get shot for saying this...but a Briggs will nearly always run and a Honda is damned unbeatable for smoothness (love my GC190). That said, when I taught small engines years ago, I stayed away from Craftsman/Tecumsehs because we could never get them going. Today I enjoy the challenge of getting bringing them back to life. They make lots of torque (HS40s shock me) and have interesting quirks about them: no two are alike and what works on one may not on the next.

 

[CLH]

I ended up being frustrated with the performance of the knock-off, $16, Chinese carburetor. Pretty bad sputtering at full throttle and the main needle didn't seem like it was doing anything. Plus I hate knock-off stuff due to its poor quality always.

I decided to put the new OEM Tecumseh carburetor back on, the same one I described was spitting gas out the bowl vent above. Because of the problem before of the spitting gas, I figured it had to be something with the float, so I took the bowl nut off. When I removed the bowl and set the carb level on my workbench, I noticed the float was sitting "high" and not level as it should be. I removed the float assembly, and then adjusted the tang of the float DOWN a bit to lower the float. (as to allow more fuel into the carb.)

Allowing more fuel into the carb seems counter-intuitive to solving the problem of gas spitting out of the carb, but I knew that small engines generally require a float to sit level (with the pin, needle and seat in, of course). The Tecumseh fired right back up and no more gas spurting/leaking out of the bowl vent!

I have heard that specific Tecumseh carbs, such as mine, have a ball bearing check-valve sealed in them as part of the bowl vent system. It allows air in at periods of time - and gasoline out in order to serve the atmospheric needs of the carburetor (don't ask me what those needs are exactly), while keeping the engine safe to use by not allowing gasoline out. You can actually hear this ball-bearing (provided it is working on your carb) moving back-and-forth by turning the carb up and down. You can also hear the float the same way. My theory is that if there is not enough gasoline being allowed into the carb via the needle, this check-valve will not be able to seat properly against its orifice. This is speculative, but would explain why by lowering the float to allow more gasoline into the carburetor, I was able to solve the problem of the spurting gas.

Oh, and after learning the hard way. OEM stuff IS in fact better than the Chinese knock-off junk. Take my word for it, buying the knock-off stuff saves NO money because the stuff fails so fast!