Galloping Onan-24

[Chuck White]

Well guys, I finished up the sawjob around 4:00PM and brought the mill home!

I started the day with a fresh 5-gallon tank of gasoline with 1 ounce of "Stabil" in it along with 2½ ounces of "Seafoam".

The galloping, searching, hunting, etc deminished quite a bit by the time the first tank of gas was about done.

Only ran about an hour on the refill.

At the end of the day, I unhooked the hose from the tank and let the engine run out of gas.

Tomorrow I'll get a little time and pull the top off the carb and see what I can clean out of there.

The gasoline additives didn't completely get rid of the problem, but the engine did run a  lot smoother by the time the day.

Almost forgot!  I tried the choke trick and all it did was killed the engine!
Funny thing about this engine, it doesn't like much choke....ever!

Thanks for all the responses to this problem, I'll come back after I take the carb apart and clean it!

[drobertson]

Well, least you got done!  a fresh start with a new week ahead and lots of info to go with, sounds like your gallop will soon be a thing of the past,  might just be a good time as ever to give an overall tune up,  sounds like these engines are some good ones! and as far as the ethanol, I think this blend has cause many of head scratching with allot of engines,   hope it all works out for you!   david

[Al_Smith]

I almost think there must be gremlins that get in the carbs some times .Unless there's  covert group lacing the gas with microscopic grit to sell new engines as might be the case .Humbug !

[Jim_Rogers]

I had a lawn mower mechanic tell me once he liked that "staybil" stuff, as he felt it worked like a carburetor cleaner.

I had a landscaper tell me once to never let your machine run dry from fuel by letting your fuel jug run dry. He said it would suck up all the junk in the bottom of your fuel jug and put it into your lines, filters, and carburetor.

You should/could pour out the last few ounces of gas every once in a while to make sure you jug is clean.

When my old 1968 Case tractor/backhoe starts running rough, I do the old farmer's trick and put my "clean hand" right over the intake of the oil bath air filter. And let the carburetor suck it down until it just about stalls. This suction will, at times, suck the junk out of the carburetor. And it will run better afterwards. My Case is an updraft carburetor, but I don't know if that makes any difference or not.

Jim Rogers

[Ianab]

The fact that the Stabil, Seafoam and new gas did improve the situation points even more towards it being crud in the carb. You managed to dissolve and shift some of it, and that made things better, but not enough to completely fix the thing.

So out with the tools and physically clean out the rest, and you should be OK.

Why is it actually "galloping"?

When you are running on a low load the governor will be closing the throttle body, make the carb work more on the low speed (idle) jet, even though the revs are still up. This isn't working right, so the revs drop off faster than expected. The governor then opens the throttle again to correct this. Repeat the process all day long.

Once you get the carb clean and working properly the engine will behave as expected when the throttle closes, and the revs will balance out with the governor action and hopefully it runs smooth again.

A broken spring or binding linkage in the governor mechanism is also a possible cause, but crud in the carb is the more likely one.

Ian

[Al_Smith]

 

When my old 1968 Case tractor/backhoe starts running rough, I do the old farmer's trick and put my "clean hand" right over the intake of the oil bath air filter. And let the carburetor suck it down until it just about stalls. This suction will, at times, suck the junk out of the carburetor. And it will run better afterwards. My Case is an updraft carburetor, but I don't know if that makes any difference or not.

Jim Rogers           

That's what I do with the old Fergy too but it's only a temporary fix .Whatever gets stuck in it just migrates some place else until it rears it's ugly head again .

I have clear fuel filter which is visable from the drivers seat and I can see if it's drawing fuel .It's just something I deal with because I have three old machines with Marvel Scheubler carbs and they all do it .On the other hand I can field strip that carb in 5 minutes  flat because I've done it so often .

[bandmiller2]

Wile we're on the subject fuel tanks collect crud and water.What I like best is a tower that extends up into the fuel tank an inch or so that keeps a lot of water and heavy sediment out of the carb,but you still must clean the tank once in a wile.A dirty trick is to put a clear plastic baggie or even a piece of newspaper in a tank,especially on a diesel.That floxom will drift around and block off the fuel, once the engine dies it will float away and you reprime thinking the problem is solved.If you have a recurring problem check inside the tank.All my tractors have an inline filter in addition to the standard one.Frank C.

[Al_Smith]

Some are worse than others about floating crud into the fuel lines .

Oh chainsaws are just as bad at times .Teeny weeny stuff goes right through  fuel filter and clogs the carb screen .

Tractors ,mowers and the like you can even have a sediment bowl and an inline filter and it still gets through .Try as I might I certainly don't have the answer to it .Clean the carb out ,cuss if you are so inclined is about the only cure .If you don't cuss give it a dirty look .It doesn't help to beat on it with a big hammer .

[Chuck White]

Well, Well, I opened the carb and there was quite a bit of crud in there.

Sprayed carb/choke cleaner removed the drain plug and brushed & swabbed the remainder out!

Repeated a few times.

Cleaned some of the jets, especially the long jet near the back of the carb.

Reassembled, fired it up and it ran like a new one!  ;D

I really thank all of you guys for your suggested fixes and encouragement!

Really appreciated.

Chuck   8)

[Magicman]

Chuck, thanks for reporting back.  Sometimes putting off the obvious only prolongs the misery.  I'll bet that you will not be hesitant next time.   ;D

[petefrom bearswamp]

Glad you got your problem solved.
Now make some sawdust.

[NMFP]

Is it fuel related or ignition related?  If fuel, clean carb and linkages.  If ignition, is it solid state or conventional.  Solid state will normally either run or not run... nothing in between.

If its conventional, 9 times of of 10 it is a bad condenser.  In that case, pull the cover off the box and replace the condesnsor and replace the points and SET THEM CORRECTLY...  Should not have any more problems.

Have many pieces of equipment that have 14-26 hp onan engines and some have over 8000 hours...

thanks,

NMFP

[Chuck White]

Is it fuel related or ignition related?  If fuel, clean carb and linkages.  If ignition, is it solid state or conventional.  Solid state will normally either run or not run... nothing in between.
If its conventional, 9 times of of 10 it is a bad condenser.  In that case, pull the cover off the box and replace the condesnsor and replace the points and SET THEM CORRECTLY...  Should not have any more problems.
Have many pieces of equipment that have 14-26 hp onan engines and some have over 8000 hours...
thanks,
NMFP

Fixed it!
See post 58.
NMFP; My engine is 24hp, any idea what the value of the condenser is?

Thanks for the input!

[woodmills1]

I used to know what a condenser was for................... ???

[bandmiller2]

A condenser is just the automotive version of a capacitor,it builds up a charge and saves the points from arching so much.And yes the condensers we get now are crap,they try to make one size fit all.Frank C.

[Al_Smith]

A condenser is in fact a capaciter .On a mag system just about any that will fit in the space will work because the primary voltage is very low .On a battery ignition you need to be more concerned about the proper value .

On a battery system if the condenser is not the correct value it will burn the points on one side or another depending if it's under capacited or over .I forgot which is which but I'm sure Mr Google could find out .