Max II with vanguard 18 hp fouling issues

[DaveL]

Have a MAX II with a vanguard 18 hp engine and after only 10 min. of operation the plugs foul. I have rebuilt the carb 2 times then replaced the carb with a new one. I have checked the timing, valves, installed new rings, coils, air filter, breather, and seals, ($500 worth of parts). Still after 10 mins both plugs are fouled. I have never had a small engine I could not repair but the vanguard seems to be a very poor choice for reliability and performance. I have had it for 2 years now and have not been able to enjoy riding it yet! I have contacted Briggs, local dealer and followed suggestion from this and other forums with no luck.

Looking for a different engine to install in my MAX, any suggestions?

Briggs use to be a good reliable engine but will stay away form them from now on.
I would recommend anyone looking a MAX to stay away for the Vanguard engine.

[timothy]

fuel foul or oil foul? - have you checked the compression on each cylinder?

[plott hound]

describe your problems at perr. Small Engine Technical Forum • Index page

these guys are really great,you will find a solution before you do a transplant.

[robertkbush]

Heres a quick fix try some antifoulers

[racerone3]

have you replaced the kill wire that goes between the coils? might be shorting out on something once it gets warmed up and intermitantly killing spark to one or both coils letting them load up with fuel

[Tom]

Does it have an aftermarket electric fuel pump?What pressure?Remember these engines only need a couple pnds,anything higher and you will float needle off the seat.Is the choke actually working?

[wfo]

i think racerone3 might be onto something..sounds like an ignition voltage issue
not hot enough spark ?

[DaveL]

ALL Thanks for all the great replies!

Compression is good
Replaced the Kill wire along with the coils
Has the vacuum fuel pump installed from the factory and the choke does work.
Have install E3 2.0 plugs the last time and was using RC14YC recommended by briggs.
What would be the next hottest plug to try?
Never heard of antifoulers may look into those as well as check out the tech forum recommended by plott hound.

Thanks for all the input.

[Roger S]

So is it gas or oil fouling.

And is the crankcase ventilation in the valley between the cylinders or in a valve cover. Have you looked at the one way valves in them. Does it throw oil onto the paper air cleaner.

[DaveL]

The crankcase vent is in the valley and was replace. Once I had oil in the air cleaner from the breather this happened after I had removed the heads and cleaned the combustion chambers and cleaned valves. Since then I have replaced the rings and have not had any oil in the breather but the plugs still foul after 10 mins of operation.
The fouling is dry black carbon. Engine starts and idles good, I get some smoke when I hit the throttle, seems to have good power and runs good until the plugs foul and both foul about the same time.

[Robinhood02]

Dry and Black and sooty is usually (just a little) too much fuel,---- wet, oily and Black is usually oil-----Grey and powdery is usually to little fuel---just plain wet is usually way too much fuel these are all prvided you are useing proper plugs !!!!!
i would check your top carb gasket for imperfections (it may be allowing fuel thru at high vacuum) or maybe the float is to high, did you just buy it ?? if so, if it came from a sea level area and you are high up in the interior float level could be a prob