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IHC 1 1/2HP M needing fuel system help

oeisales

Registered
I am hoping someone on here can lend a hand with our IHC 1 1/2hp M engine. We put in a new fuel tank, replaced the fuel pump and basically stopped all the leaks. Now, after doing all of that, we can't keep it running. It will start, run for a few minutes, then start to run away, then once it slows down, it starves itself for fuel. We usually can't get it running then unless we prime the carburator. I checked the carb, the little wall if you will is still in tact, so fuel does stay in the carb and doesn't run back into the tank. If I adjust the governor assembly on the head, then it seems to run too slow and won't pump enough fuel. Any help would be greatly appreciated.

Thanks,
Bob Loos
 

Glenn Miller

Subscriber
Last Subscription Date
12/16/2019
Re: IHC 1 1/2HP M needing help

On my m the fuel will pump up to the mixer by just useing my thumb on the pump. it must run over the little wall to keep the engine running. if not the engine will stop. if you have to put gas in the mixer to get it started, that might be all the gas the engine is getting when it runs away then runs out of gas. try releaseing all the spring tension on the thumb screw located back at the main bearring by the flywheel so the butterfly on the mixer works freely then close the needle vavle for the gas and start by opening a few turns at a time till the engine starts and runs about 400 rpms or so. maybe this will help you out. good luck. Glenn.
 

David Hughes

Registered
Re: IHC 1 1/2HP M needing help

There is a very specific adjustment for the gov adjustment at the head--something about the thickness of a well worn dime. It sounds like it is starving for fuel--are you sure the fuel pump is pumping? Perhaps you should disconnect it at the carb and spin the engine with the intake valve held open and make sure it pumps. The carb is supposed to fill with fuel, with the overflow flowing back to the tank, this establishes a constant fuel level in the carb.

If you don't have the IHC shop manual, you should get one--it describes the adjustments. Available from our suppliers

David Hughes
 

oeisales

Registered
Re: IHC 1 1/2HP M needing help

I bought the fuel pump new from Hit N Miss, but I will check it again. I had to file it down some so that it would come back up against the fingers freely, but maybe it isn't lose enough. Thanks for all the suggestions!

Thanks,
Bob Loos
 

John Hamilton

Subscriber
Last Subscription Date
05/25/2019
Back in the day if you had let your M sit a while you would pump some gas into the mixer with the little lever over the pump. Look in the mixer to see that gas is actually coming in. If not, that's the problem.

It probably runs away because that's what engines do when they are running out of gas. It won't restart because it ran out of gas.

If it's pumping make sure the little pickup tube to get gas out of the resevoir is not stopped up. You'll have to take the top off the mixer to do this. Take the needle valve out, hold your finger over the hole the needle goes into and squirt carb cleaner into the valve hole. It should come out the little tube. If it's stopped up it won't suck up gas even if it's there.
 

oeisales

Registered
John, thanks for the advice. We blew out the carb with an air hose, but cleaning it with carb cleaner is a good idea. We also cleaned up the new fuel pump tonight, reset everything and hopefully can see if it will start tomorrow night.

Thanks,
Bob Loos
 

KidDynamo

Subscriber
Last Subscription Date
02/18/2020
With the fuel tank installed under the engine and sort of hidden and the fuel suction pipe coming out of the top of the tank, it is easy to get an air leak in the suction line at one of the fittings.

I had to deal briefly with this issue with my "M" to get the pump to work properly. Getting the fittings all tight and the pipes all aligned so they will fit through various holes and connect where they belonged required a bit of patience. Once the engine is lowered back onto the skid, you can't "tweak" the tubing or a leak may be created, especially when re-using the old fittings.

Just when it looks like everything is correct, one little turn of a fitting to get everything simultaneously positioned correctly can open an slight air leak, and one tiny air leak in the suction line is enough to prevent good pump performance.
 

oeisales

Registered
Bob, the tank is vented, and Kid, thanks for the advice. I have installed teflon tape on all the threads that I thought needed it. We are hoping to try to get it running tonight, I'll keep you all posted.

Thanks,
Bob Loos
 

David Hughes

Registered
On my 3 hp M, since I had to make up some of the fuel lines, I installed an antique fuel filter (Zeneth [sp?]) with a glass bowl, as well as an antique petcock (I think it was off a Model T Ford oilpan), both on the suction side of the fuel pump. I can see if fuel is pumping through the glass bowl, and I use the petcock to break the suction to the fuel pump so the fuel in the carb gets used up before shutdown

David Hughes
 

oeisales

Registered
Ok, I'm still pulling my hair out lol.......it runs great when the fuel tank is completely full, but, once the fuel runs down, it stops pumping. I am starting to wonder if I put the new fuel pump together incorrectly. How many check balls should there be and how many springs holding the check balls in place should there be?

Right now I have under the pump push rod cap with fingers is a spring, then a sleeve, then packing, then a check ball in the bottom. Under the line going to the carb, there is a check ball and a very light spring holding it in. Is this the correct set up?

Thanks,
Bob Loos
 

oeisales

Registered
Gaining some headway! I read some where about the size of the check balls being different, so I made sure they were in the right sleeve. Primed it some, and finally got it to work right for about 15-20 minutes. Then, the carb went dry again. Not sure, but maybe the fuel pump just needs to have a break in period. Anyway, thanks for all the suggestions!

Thanks,
Bob Loos
 

Glenn Miller

Subscriber
Last Subscription Date
12/16/2019
hey, its me again. you haveing said you purchased a new pump just brought back memories on my m. had all the same troubles with mine that you had and tried just about all of the same.finialy one night I had enough, cut a 1/4 inch off the shaft of the pump put it back together and the engine has been running good for years. the shaft was to long and not going up past the fuel line that suplies the fuel up to the mixer. not letting fuel enter the line. by the way my pump leaks a little but it has never seem to keep the engine from running good. my friend has an all original m and it leeks but runs beautiful and I have seen a lot of m's it seemed to be just one of there characteristics. anyway good luck. Glenn.
 

oeisales

Registered
Glenn, I honestly never checked that. I will have to see how it compares to the original one tomorrow. It is getting better, like I said, had it running for awhile tonight then it just quit pumping again. As for the leaks, I know what you mean.

Thanks,
Bob Loos
 

Dale Barnett

Registered
Last Subscription Date
09/24/2013
Just a quick question for you.
Is you packing tight and do you oil it.
I have a 1 1/2 hp M that will run with just one of the ck balls as long as I keep the packing snug and oil the packing about every once in a while.
I did get it fixed with both ck balls and still find a little oil on the packing helps a lot as the packing must seal or it sucks air and won't pump fuel.
 
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