Small engine frustrations

Topic: Small engine frustrations (Read 1214 times) previous topic - next topic

Small engine frustrations

November 10, 2011, 06:16:01 PM

Hey all, if I remember correctly, there are a few folks here that are good with lawn equipment and small engines. What I'm dealing with is a troy-bilt chipper vac with a tespoogeseh 5hp horizontal shaft engine. the problem is that it won't start warm unless you gag it with starting fluid. The carb was thoroughly cleaned by myself and supposedly rebuilt by another neighbor (this unit belongs to another neighbor) though I did find today that the float bowl gasket was improperly seated. The plug is new and clean... Still to no avail it will start fine from cold but once its warm its game over. The engine runs great once it is running handles a load fine and idles smooth.

Any ideas?

Small engine frustrations

Reply #1 – November 10, 2011, 07:25:05 PM

Modern gas varnishes in months. It plugs up the tiny holes in the passages of small engines all the time. I am CONSTANTLY fighting it in my tiller, ATV, and mowers.

You have to pull the carb and clean ALL the holes and it'll work. I just sold a snowblower I bought at s value that had the same problem. Guess what? The carb had been 'professionally ' rebuilt recently. They missed a passage that was smaller than a pin.

Honestly, tough. The gas stinks these days. It just won't last in storage.

Small engine frustrations

Reply #2 – November 10, 2011, 08:00:52 PM

Well, considering that this thing has sat for over two years I'll give the carburetor another look. I do know that right after my neighbor brought it home the first thing I did was pull the float bowl off and the fuel inside was green, and I had him blow onto the fuel tank with the float valve open and some brown/green substance came out. Is there anything that needs to be checked in terms of the governor? I'm used to dealing with air game governors as seen on Briggs vertical shaft but this one appears to be internal. Also, any ideas on what the needle valve that goes into the bottom of the float bowl controls? I know that before the other guy rebuilt the carb it had an issue with dying under a load and turning that screw in some solved it.

Thanks for the help so far.

Small engine frustrations

Reply #3 – November 10, 2011, 08:59:08 PM

Yeah they're honestly pretty finicky if ANY contamination has actually gotten in there. Fortunately they're as simple as they look. Either the coil is dead or the carb is messed up. Not much to go wrong with the little things still to this day. The bottom screw is high speed mixture, the one on the side of the carb housing going outward is your low speed. Ought to be somewhere between a turn and two turns on each really, neither should need to be backed out so far they're barely clinging to life, if they do there's something else wrong. Take that carb out, yank all of the needles and parts off of it and fill a coffee can with B12 Chemtool, thinner, carb cleaner, depleted uranium I dunno LOL. But a good strong cleaner. Let the thing soak overnight if in doubt. And get new seals for anything in question, cheap enough. Also if the bottom of the bowl is NOT 100% flat, has a slightly higher and lower stepped down portion, make sure it's rotated so that the end of the float hanging down farthest sits IN that depression area. Kind of a subtle thing but important, you want that float to let as much fuel flow in as possible when it needs it, that small height change does make a difference, did for me anyway. Was pissed when I found out.

And on that governor if everything is there and hooked up, make sure when it's off, totally stopped, throttle is at wide open, no spring tension pulling it at all. When it's running and at idle, whack the throttle by hand to rev it up, gov should pull against you pretty hard if you try to over-rev it. There may be an adjustment screw with a torx head or something otherwise, there SHOULD be an adjustment anyway. That will adjust how much extra tension the spring on the actual "Speed Control" lever the splitter/mower/unit powered by the engine exerts on the throttle linkage to overcome the governor spring, and at some point you get it where it stabilizes the throttle at the right speed for "Fast" speed but not so much tension that at "Slow" / "Idle" it's still tugging on the throttle and not letting it back to idle.

Small engine frustrations

Reply #4 – November 10, 2011, 10:20:06 PM

A couple odd things about this yard vac... first when I got it back from the alleged rebuild, the float bowl was rotated 180 degrees, meaning the raised portion was in effect holding the float up higher than it should have. Also, even though it has a 4 speed transaxle with a differential, park, neutral and reverse, there is no speed control for the engine. Also, looking through the owners manual I found the purchase date written as august 1992! Looking at this thing I wouldn't have guessed it was older than the two years it sat in storage. There's even a receipt from 1993 where the guy dropped $100 on the optional vacuum hose kit. Funny considering my neighbor bought the whole thing for $50!

I'm still at work now but when I go home I think I'll tear back into this thing.

Small engine frustrations

Reply #5 – November 11, 2011, 08:21:51 AM

Wow nice little history trace haha. That is cool though and back to my point about them not changing much in the last FIFTY years lol. Okay so it's an entirely self-governed engine. Should still be an adjustment somewhere for what's in this case, only a spring ancd to some spot, not to a handle you can move. So if it seems like it just runs slow, you can adjust that, the spring does wear out, I can't count how many older lawn mowers I hear running at probably 2500 rpm instead of 3000-3100 like they should and they sound like they're about to croak on the spot. Not the thing losing power, gov just worn out LOL. Even after years of neglect and lack of oil maintenance small engines take foreevvvvvvverrr to loose compression.

Small engine frustrations

Reply #6 – November 11, 2011, 11:09:26 AM

So is it safe to soak the whole carb body in a solvent? All I've removed is the float bowl, float, pin, needle valve and the speed adjustment screw that goes into the side. It appears that that's all that can be removed.

Small engine frustrations

Reply #7 – November 11, 2011, 01:26:00 PM

First

Small engine frustrations

Reply #8 – November 11, 2011, 02:48:02 PM

Their is little holes on the bottom bowl valve that need cleaning to,you say it runs and starts cold fine? If it doesn't start hot it may be a valve adjustment issue." heat expansion holding valve open a hair loosing compression". One thing about a 1 cylinder you need spark,fuel and compression,or it will not run,not like multiple cylinders. You can check the governor to see if it is working by running the motor and choking the engine and see if the throttle arm trys to open all the way. It won't tell you its adjusted right, but will tell you its working. If it is a set gov. speed theres different springs or holes that the spring goes into to determine the rpm.

Small engine frustrations

Reply #9 – November 11, 2011, 08:12:46 PM

Well today before work I tore into it again, bought a half-ass rebuild kit that had needle valve, seat and bowl gasket. And after I cleaned everything I could get to, including those small holes in the float bowl valve. Once I put it back together it ran great. I didn't have to adjust either needle valve screw (I set them both around 1.5 turns out from fully closed) and all was well, I let it warm up, used it some and purposely stopped it and restarted it and all was well. But, I had to get ready for work, so I let my wife take over and within about 20 minutes it stumbled and died 5 times. I'm lost again.

A couple things to note, I have a bad feeling about the air filter as the last time I restarted it there was a grayish smoke from the exhaust once it fired up, making me think it might've been running rich. Also, there was a rubber gasket inside the fuel cap with holes in it but my neighbor took it off because it wouldn't stay in and nearly fell into the tank a few times. Is that part of the cap necessary so as not to create a vacuum lock inside the tank?

Small engine frustrations

Reply #10 – November 12, 2011, 12:25:10 AM

Check the bowl if you want for debris...maybe the line is full of shiznit slowly coming unglued...never know. Air filter, obviously check, if obscenely clogged with dust and , blow out thoroughly with compressed air if you can't get another one, ideally get another one. You can definitely test it without the thing even in place, just make sure there isn't dust getting kicked up nearby, it'll be just fine temporarily. Caps are usually vented themselves, the gasket I'm assuming is a flat solid disc? With holes poked in it? Not like an O-ring type? Again the cap itself is usually vented so without whatever gasket came with it, it would just be more likely to spill fuel out quicker if knocked on its side. When it dies, take note of how...surging up and down and petering out as if you just loaded it down with a massive brake? Or sputtering, puffing smoke, etc? I feel like it's most likely running out of fuel. That is unless the mixture is too rich so that once it warms up it's loading up with fuel.