Predator engine

[jaoneill]

A couple of years ago when the engine quit, I re-powered my 6x4 Gator with a twin cylinder 22hp Predator. My brother repowred his splitter with one years ago and has had good luck with it ( other than hard starting in cold weather due primarily to the carburator being tuned to meet Kalifornia regulations) so it seemed like a good alternative. I have had ongoing issues with the float valve sticking and it dumping gasoline into the base. Turns out that many of the neighboring Amish use these 2 cylinder engines as well and most have told me that they have the same problem. The issue appears to be a design or manufacturing flaw. It isn't that the valve itself sticks but that there isn't enough clearance between the float and the bowl; the float hangs up on the housing. Anyone else out there with this problem (or a solution).

 

[blades]

What is the float made out of? in years past floats were hollow bulbs of something then there were cork ones, some of the stuff I have seen lately are just a plastic tube of various shapes a little investigation of clearances might yield a simple fix as some sand paper or a minor hammer adjustment ( redneck style) Ethanol does play a part in the sticking as well, particularly on engines that sit idle for several months at a time, dang stuff evaporates out of the petrol leaving a film behind as well as attracting h2o which causes a combination of the film and oxidation to build up.

 

[jatoxico]

If you can confirm the float is hanging up on the housing then I agree w/ blades, trim/sand and otherwise massage until it swings freely.

 

[jaoneill]

What is the float made out of? in years past floats were hollow bulbs of something then there were cork ones, some of the stuff I have seen lately are just a plastic tube of various shapes a little investigation of clearances might yield a simple fix as some sand paper or a minor hammer adjustment ( redneck style) Ethanol does play a part in the sticking as well, particularly on engines that sit idle for several months at a time, dang stuff evaporates out of the petrol leaving a film behind as well as attracting h2o which causes a combination of the film and oxidation to build up.

It's been six months since I last had it apart and I can't remember for certain what it was made of but I'm thinking it was an old fashioned hollow brass type float or flimsy hollow plastic bonded to the brass hinge, not something that could stand to be whittled down at all. At the time I tried the push, bend, pry method to adjust its travel path to where it seemed it might be ok, (and it was for a time) but it is such a close fit all the way around that there simply isn't much space for it to move in.
Rare is the day that I don't use the machine and buy nothing but unleaded gas so I think the ethanol problem can be ruled out.
A new carb can be had for about a hundred bucks but since this seems to be endemic to these things a new one will very likely have the same problem.
I am going to have to take the carb off again regardless, knowing I can get a replacement reasonable I will feel free to take more liberties with the existing float. Thought that it wouldn't hurt to see if someone else might have discovered a better, sure fire solution.

 

[jatoxico]

So here's an idea, maybe not a great one but here goes. I wonder if you drilled the float pin holes on the float to be slightly oversize so the float can move backwards just a smidge. Assuming you can get a replacement float for the Predator engine cheap. I guess it might also cause the float to ride a little higher letting in a little more gas to the bowl.

Either that or a couple taps on the bowl each time you put it to bed. Anyways just throwing it out there.

 

[jaoneill]

So here's an idea, maybe not a great one but here goes. I wonder if you drilled the float pin holes on the float to be slightly oversize so the float can move backwards just a smidge. Assuming you can get a replacement float for the Predator engine cheap. I guess it might also cause the float to ride a little higher letting in a little more gas to the bowl.
Either that or a couple taps on the bowl each time you put it to bed. Anyways just throwing it out there.

Reaming those pin holes could be an answer. Tapping the bowl isn't practical; aside from the fact that it's under the bed of the Gator, there is a full cowl over the engine and it takes a screwdriver, 10 mm socket and 15-20 minutes to even get to the bowl. This doesn't happen while the machine sits; the gas tank is remote, the engine has a fuel pump, float sticks while I'm running it and the first, and only, indication is when it starts billowing smoke out the exhaust because the gas in the base has raised the oil level to a point that it gets into the combustion chambers. Then I shut 'er down, drain and replace the oil and dismantle enough of the cowling that I can get to the bowl to tap, tap, tap.

 

[Jags]

Fuel shutoff valve. I have them on a couple of old tractors where the tank is higher than the carb. Even in the case of a sticky float it won't allow fuel to siphon out of the tank.

 

[jatoxico]

According to OP this is a problem during operation.

 

[jaoneill]

Fuel shutoff valve. I have them on a couple of old tractors where the tank is higher than the carb. Even in the case of a sticky float it won't allow fuel to siphon out of the tank.

This is an operational issue; th tank is considerably lower than the engine, it's when it's running and fuel pump is active.

 

[Jags]

Got it. Just learning to read so my comprehension is still lacking.
What are the chances that there is a different style of carb that would fit this engine? Might be worth a little investigation.

 

[jaoneill]

Got it. Just learning to read so my comprehension is still lacking.
What are the chances that there is a different style of carb that would fit this engine? Might be worth a little investigation.

Actually, my first inclintion was to replace the carb with a honda carb (Predator is a chine Honda clone) but Honda has 10-12 iterations of their comparable engine, many visibly different (honda parts site wants a serial number for a search) so going with one of those would be a crap shoot. I may stop in at the local small engine parts supplier tomorrow with the float in hand to see what he might have on the shelf.

 

[VirginiaIron]

Reaming those pin holes could be an answer. Tapping the bowl isn't practical; aside from the fact that it's under the bed of the Gator, there is a full cowl over the engine and it takes a screwdriver, 10 mm socket and 15-20 minutes to even get to the bowl. This doesn't happen while the machine sits; the gas tank is remote, the engine has a fuel pump, float sticks while I'm running it and the first, and only, indication is when it starts billowing smoke out the exhaust because the gas in the base has raised the oil level to a point that it gets into the combustion chambers. Then I shut 'er down, drain and replace the oil and dismantle enough of the cowling that I can get to the bowl to tap, tap, tap.

Is the pump pressure too high and overcoming the float valve?
Do you know what your fuel pump pressure is?
It seems to me, if you were getting too much fuel in the carb during operation your engine would run rough long before you had oportunity to fill the crank base with fuel.
My quad would fill the cranckase with fuel when shut off for long periods of time, due to the bad fuel cutoff.
If your pump pressure is not too high, I would try an oil/mix in the fuel to give the carb some lube.

 

[VirginiaIron]

My brother-in-law swore he always purchased E-free gas from the reputable station down the street for his quad, but the carb looked like a green/blue oxidation with a Vaseline-like goo in it. I think he was paying close to $4gl.
To keep the station honest, one should test every so often.

 

[jaoneill]

I may have found the problem. Pulled the carb today and looked very, very carefully at the float. It is hollow plastic, with a multi curved shape that follows the configuration of the "bowl", fabricated by glueing or "welding" a base and a lid to the curved sides. The arc of the float as it travels up and down has the "top", or leading edge within centimeters of, or even lightly scraping the bowl midway through its travel, and that edge had a "rough" spot along the joint between the top and side of the float. Had other fish to fry today didn't have time to attempt a fix but I'm thinking a touch-up with some fine emory cloth will do the trick.

In response to the last comments above: the fuel pump is a simple vacuum powered pump integral to the engine. Never, ever buy E-free gasoline from an all-in-one gasoline pump with a single hose, the hose, plumbing, and pump will always contain a gallon or so of the previous purchaser's regular. If you fill a 2 gallon can you have 50% garbage gas......

 

[VirginiaIron]

By your description of the seam scraping the bowl, I would say that you found your problem.

 

[jaoneill]

By your description of the seam scraping the bowl, I would say that you found your problem.

I do believe that the problem has been resolved but I've only used the machine a few days since the fix. We've had a warm/cold and wet fall that must have caused condensation in the throttle cable; bloody cable has literally been frozen for the last two weeks. That would be the only explanation for water in a waterproof, plastic shielded cable that runs through an interior "chase" from front to rear of the machine, completely protected from the weather, and has both ends facing downward. Supposed to reach the high thirties tomorrow, I'll see if I can force some isopropyl an/or penetrating oil into it.