Magnum Problems

[ambler 0]

7119 I have with M20 stopped a couple weeks ago. With all the mowing and tilling I just pulled it up to the garage. Initial symptom was that it acted flooded and then stopped cranking over. I pulled the shield on the starter side and the starter wasn't jammed in the flywheel. I turned the flywheel and gas poured out of the plug hole. Looked at the other cylinder and its full too. Bet its carb float, any other takers.

[PMax4041 0]

I Would Agree

[ambler 0]

There appears to be gas in the crankcase, at least dipstick smells like it. I have to pull heads to drain gas from cylinders and I guess drain and replace oil. Is this a fixed jet walbro and is the electrical bit the optional kill switch diode?

[comet66 0]

Where does that fuel pump pull its vacume from? I've never bothered to look, but could it be getting by the diaphram? I have seen a sticky carb. float do this in a car engine.

[UCD 14]

Ambler You shouldn't have to pull the heads to get the gas out of the cylinders. Take the spark plugs out and once this is done the hydraulic condition is removed and the starter will turn it over and blow the gas out of the cylinders. A few fast spins and the cylinders should be dry. With the plugs removed any gas left will evaporate in a few hours. Drain and change the oil and after you find the source of the gas in the cylinders you will be good to go.

[ambler 0]

The problem is the electronic module and the spark with all that gas. Can't ground it or it will burn out. Figured out what that gizmo is its the solenoid for anti dieseling.

[HubbardRA 19]

Ambler, I had an 11 Hp B/S vertical shaft engine do that three different times on me. It was random and I never did find the cause. It would run for a month or two, then suddenly wouldn't turn over. Float would stick and fill up the crankcase with gas. It would leak into the crankcase thru the breather tube. There was no tank shutoff on that machine. The anti-diesel solenoid is a direct shutoff of fuel to the carb jet. If that is working, then there should be no way this could happen unless there is a crack in the carb.

[ambler 0]

I hope I don't have your experience Rod. Got the carb off. Float is OK no gas inside. Kohlers have a fuel pump must have siphoned through carb directly into the manifold down into the cylinders and arround the rings to the crankcase. Drained a gallon of gas and oil out of the crankcase, even filled up the oil filter. Breather tube on Kohler is above carb. I'll put a new kit in it. John I think its a simple mechanical fuel pump driven off the cam. I've run this for two and a half years with few problems.

[JoeJ 0]

Ambler, It happened to me just once. It was a twin Kolher on my Hobart welder. As I checked the oil every morning before start up, I have no idea if it would turn over. It was WAY over full and smelled of gas. I drained the oil and changed the filter, plus added a shut off. It never happened again the rest of the time I owned it. Joe

[D-17_Dave 12]

I see this all the time on cars and trucks. The fuel pumps can fail several ways. Gas can leak to the outside onto the engine, gas can leak into the crankcase, or oil can leak outside onto the engine. The most common is gas leaking into the crankcase. I just had this condition on my 620. With the electric fuel pump and a tank of fuel over 3/4 full the as will siphon slowly past the needle valve and hydro lock the engine. The cyl's were full and the crankcase had 2 gallons of gas in it. But I caught it when I cranked it soon enough not to do any damage. Just changed the oil and pulled the plugs as Maynard said and cleaned it right out. It needed an il change anyway.lol It got cleaned good in the process. Any small amount of gas inside the engine after draining and refilling w/ oil will evaporate quikly into the breather so you shouldn't have anything to worry about. My Onan smoked a bit after being serviced as the rings had to reseat, but after a few rounds under load and heat it returned to it's prior condition.

[BLT 717]

I have a strict policy with one execption right now. If the fuel supply is above the carb float, install a fuel shut off. As much as I praise Briggs, they are notorious for dripping carbs. I think they more then their fair share of of bulletins to do this or that. I have saved money by just installing a $5.00 or less valve. There isn't any reason to have a fuel supply fed by a fuel pump that is higher then the float. My exception to date on fuel shutoffs is my Tecumseh V70 in my JD 60. To date no carb leaks. The fuel supply on an empty tank is about 6" Go figure. If you drain the contaminated crankcase after an hour's running a couple of times you should be ok. Dave I'm confused. How can fuel siphon up? Or do you have an over head fuel supply?

[ambler 0]

It's done. New needle valve and going to install cutoff. Smoked like a bandit for a couple minutes. I started and stopped it a few times to circulate the oil. I'm a virgin no more to this. Thanks for the help This site helps good for moral encouragement.

[aokpops 0]

I found out how to do this from this site . if you are on flat ground .just on hook the fuel pump . ran this way for three years no problems .

[MrSteele 483]

Remote fuel tanks mounted above carbs have ruined many engines! Gravity fed carbs give little problems, but, a fuel tank shut-off is a definite must on any brand of engine, any age, electronic or not. And remember to ALWAYS shut the gas off when you stop the machine, even when going in for a sandwich.