Small engine repair question

I'm wondering if the motor has one of those "easy-spin" designs - usually a late closing intake valve to bleed pressure down at starting speeds , but which intake charge velocity negates at higher RPM's . And if you've built car motors , a small engine should be a piece of cake . Doubly so if you've done auto trannies , I won't touch one ... the one thing on a car I won't tackle .

As strange as it sounds, please try an oil change. The drain plug on the side, one side or other. Use a good brand of oil. Castrol GT is my favorite. Old oil can do some strange things.

Same on the gasoline. Most places have "gasohol" now days, but buy a good brand.

Please remove the motor cover, and clear any traces of oil, dirt, cut grass, etc. If the fins on the motor side are dirty, the motor will run hot. And kill the motor oil early, as with some other problems. Use engine cleaner foamy spray, or oven cleaner spray to strip it down to the paint. Rinse well. A hot running engine can do strange things.

Seriously, the simple stuff is the important stuff.

Your barely broke in hour wise...

Did you open the throttle and choke all the way, air cleaner maybe off when you did the compression test?

Are you sure it is firing on both cylinders? You should be able to unhook one plug at a time and listen to how it sounds/acts.

If it has sat with gas in the carb over several winters, as the others have mentioned cleaning would be a good start.

I've had good luck finding Briggs manuals online for download. Your local library may have some repair manuals too. I buy the old ones when the library purges them. Lots of good info in them.

This is the most significant symptom. Likely a dirty carb, especially if it sat over the 6 winters with gas in the carb. These carbs are dirt simple - tear it down & clean thoroughly, THEN see what it runs like & worry about what else might be wrong, if anything.

"Sooty" is too rich, as you know. Why one side & not the other is puzzling to me, but I've never worked a twin. But clean first, then check again.

You can't do compression checks on these engines - it's meaningless. Well, twins may be different, but I doubt it.

Clean the carb.

Bob

Okay, seems like you are all saying that compression check (V-Twin with starter motor) is kind of meaningless. Ergo, I will start by cleaning out the carburetors. BTW, I have never believed in the 'old gas' theory since my small engines have always started after a winter of sitting idle. Best example is my 5500 watt generator. Sits for two years but starts on the first pull even though the gas is 24 months old. (I do let the carburetor run dry when I shut down).

Now maybe I've become a believer. I will dump the old gas, clean the carbs, change the oil, install new plugs and give it another try.

Thanks,

Ivan Vegvary

If this just started I would say it's two problems. One is crud and crap that built up over the years has been flushed loose by the alcohol in the current gas. The second is the current alcohol content in the gas. It causes the engine to run lean usually, causing sputtering and lower power.

Doesn't mean anything on these newer Briggs engines. They have a weird compression release that makes it hard to test them unless you turn the engine backwards.

Sooty black is usually rich running BUT on the V twins it is a sign of a weeping valve stem seal. They can be changed easily without tearing down the engine. You can also adjust the valves at the same time.

Good. That means it's just started.

Nope. I have well over 800 on a Cub Cadet with an 18 HP V twin. Burns a little oil but runs great.

Won't make much difference unless you can figure out how to crank the engine backwards.

What I would likely do is - Clean out the fuel system, replace the inline filter, clean the carb. Install a tune up kit (most dealers have them on the shelf, includes a new oil filter, air filter, plugs, gas filter and oil).

Then try to buy gas that doesn't have alcohol in it if possible. If not there is an additive you can buy that will help keep the gas/alcohol from separating while the tractor isn't being used. If you buy your gas in quantity and have it sitting around over a couple weeks you might want to lower the amount you keep on hand and rotate it more often.

I've got a short cut cleaner - sea foam. Put in spray bottle and spray in carb while running. Do it several times. After that put a bunch in the gas tank with it nearly out of gas. Qucik and dirty - normally works wonders on my gravely kohler engines. After this, I pressure wash the engine, new plug, new filter new oil. engine runs like new.

Works on 2 cycle also

Karl

...

Ah ... my point about sitting over winter was not "old gas", but gas evaporating in the carb & leaving deposits. If you stored it with a dry carb, as you say, this does not apply.

I'd still recommend cleaning the carb(s?), just based on the performance symptoms.

Bob

Do yourself a favor..and buy a bottle of Sta-bil gas stabilizer and dump the proper amount in the gas tank, and run some through the carby before shutting it down for the season.

The stuff works Great!, is used by major corporations, the military, government agencies and a shitload of us who only use gas powered equipment a few times a year.

I have a number of gas welders, gennies, weed eaters, mowers, chain saws etc etc etc..and they all get FRESH gas AND Sta-bil before shutdown.

Gunner

--Don't forget to change out the fuel filters; there may be more than one (my Kubota has 2). Also it's old enough that you might want to change out the fuel line tubing; that stuff gets old and may shed debris in the fuel lines..

No directions, but encouragement: I got one of those things after it had already been worn out at least twice, and wore it out once more before I gave it to a neighbor who wore it out again.

Just keep fixing what breaks; there's no wrong way to repair a piece of crap as long as it keeps going and doesn't injure anyone.