Mcculloch 14 wont stay running more than a few minutes

[14altra]

This is my first small engine motor Im used to larger outboards. I bought a new tank put 2 gallons of fuel and 7 oz of oil which should be 40:1. I may be running to rich but I didnt ant to chance it. The cowl shows 16oz for 4-6 gallons of fuel which is 30 or 40:1. 7 is between 30-40 to 1.

The problem is the engine wont stay running. I can get it to start but after 4 or 5 minutes it dies. There are multiple adjustments on the front. Choke, idle, and high speed. I set them all at the suggested settings under the cowl and it will start and run and I can even push in the choke and I seem to be able to smooth it out with the high speed setting.

One thing I noticed is that I cant get the primer bulb to get firm. When I pump it fuel comes out of a little hole in what I think is the fuel pump. The bulb on my last outboard, a 90hp mercury, would get rock hard. I dont think fuel should be coming out. Someone told me its an overflow/pressure relief so you dont rupture the pump diaphragm.

Any help would be very appreciated. I would like to be able to grab an hour or two fishing once in awhile. I have pics but I dont know how to upload them.

 

[DaleH]

Try pumping the primer bulb while the engine stalls and if it keeps it running I would say it’s your fuel pump. I am not familiar with that motor but I have never heard of such a relief that would spray gas out the fuel pump ...

Hope that Pappy chimes in, he’s the expert’s expert!

 

[Weldorthemagnificent]

Make sure it's pumping water and not getting hot. Should be able to touch the side of the engine. That's an old motor. Compression, spark and fuel are all things to check. The fact it runs probably speaks to compression, could be a cracked coil getting hot. Do the bulb squeeze as mentioned and eliminate things one at a time. And when Pappy chimes in, do what he says and forget the rest of us. Lol. Good luck!

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[MrGiggles]

I agree with Dale, sounds like it is only running on the prime and quitting once the bowl runs dry, not drawing anything up from the tank. Like he said, try squeezing the bulb as it's running.

It should not leak anywhere. There is no purpose-built pressure relief, however the needle can be pushed off the seat if you apply enough pressure to the primer, causing the carb to overflow, but you really need to squeeze hard. The firmness that you feel in the bulb is from the carb needle shutting off fuel flow.

I'm guessing that there is a hole in your fuel pump diaphragm, and fuel is leaking out through the vent/weep hole.

 

[14altra]

Parts seem to be not as common as most. Can I use a newer fuel pump? Its a diaphragm fuel pump and it has three lines which I would assume are, in, out, and vacuum. Its only held on by two machine screws. It doesnt seem that it would matter as long as it is supplying enough fuel to the carb or am I completely missing some fundamental basic issue?

 

[Weldorthemagnificent]

Probably a lawnmower pump be the cheapest option

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[14altra]

It may sound stupid but that is what I was thinking to see if that fixes my issue. I looked for a diaphragm for this motor and couldnt find one

 

[Pappy]

You definitely have a diaphragm failure in the fuel pump. The fuel leak is the tell tale on that.
Yes, pretty much any fuel pump you can find will run a 14hp engine. Find one with the same number of fittings for inlet/outlet/pulse line.
On the primer bulb......the bulb will only stay firm when you are pumping it and the needle is seated in the carburetor. Remember the bulb is on the suction side of the fuel pump and therefore will not stay firm while the engine is running.
Once you rectify the fuel pump then work on your High and Low speed carb settings. The manual will only give you rough initial settings. At idle richen or lean the mixture (in the water) until you get as smooth an idle as possible then richen a touch. On the high speed you want the most RPM you can achieve (in the water) and again, richen just a touch.
Your fuel mixture is not too rich. I run my antiques on a 16:1 mixture all the time and they have a much less robust ignition system than your engine does.

 

[14altra]

Thank you! I found a fuel pump for a twin koeler 15 to 25hp with the right number of lines. Ill order it and adjust as you suggest. Ill keep the ratio at 30:1 as it says.

 

[14altra]

I got the fuel pump on and it runs and idles well on the hose. Im going to try and get it in the water this week and see if I cant get it running smoothly.
Thanks for the advice. Hopefully it works well in the lake also.

 

[Weldorthemagnificent]

Nice!

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[14altra]

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