Jump to content

Unofficial Home of Old Simplicity & Allis-Chalmers Garden Tractors

7016 won't fire


Commissioner

Recommended Posts

Commissioner
I have a 16HP Briggs that seems to have a good spark but won't fire (even with a little gas or starting fluid in the plug hole). The key is in the flywheel so it doesn't looked like it "jumped" timing. The engine probably has about 10 hours on it since a dealer replaced the cam and put in a crank that was in better condition. It ran fine and strong then just slowed down and quit. There are no numbers on the block or cover. The block was from a engine that ran the compressor on a refrigeration truck. That block was put in about 15 years ago when the original block got beyond repair, the original head was kept. Moving the crank by hand there almost feels like there is a little play, don't know that is normal or expected in a 'seasoned' engine. I welcome your thoughts....haven't spoken to the dealer yet.
Link to comment
Share on other sites

I guess you need to do it with a Briggs spark checker, or get about 3/16" spark length and it you get a spark with that, you have a fuel problem.
Link to comment
Share on other sites

My thoughts... Gasoline or starter fluid in the sparkplug hole might be too rich to fire and probably wets the plug. You might try WD-40 or a silicone spray through the carb. I wouldn't recommend using starter fluid through the carb though. Way too explosive for those one cylinder engines. Steve
Link to comment
Share on other sites

You mention feeling a little play in the crankshaft... I wonder if the flywheel key is partially sheared, giving you some play, and also getting it far enough out of time that it won't fire....
Link to comment
Share on other sites

Commissioner
Kent....I actually pulled the flywheel and was moving the front and rear shafts simultaneously ever so slightly by hand (with the plug out) and that is where I was detecting a slight play. I thought just maybe this play was throwing off the timing. The key appears to be all there.
Link to comment
Share on other sites

If the play is back and forth, ie front to rear, that is called end play and I belive there is suppose to be .002 there. To ruughly check your timeing see if your points open just before top dead center on the compression stroke.. MPH
Link to comment
Share on other sites

If the stroke is at the top or the bottom, you can move the crank ever so slightly and it will feel like you have a bad wrist pin or rod/crank. This is normal. There is clearance between the rod and crank so that it will get oil and not burn up. If you have fire, the flywheel key is not sheared, and you have compression, You can almost be certain that there is a fuel problem. I had a briggs do the same thing to me. It really had me frustrated. It would not hit at all. I finally remembered an old trick that my Dad used on the Farm tractors when they got balky about starting in cold weather. He would remove the air intake hose off the carb from the air cleaner and cover the air horn with his hand and have someone crank the engine. I tryed it on the briggs I mentioned and it started almost immediately. I replaced the carb mount and intake gaskets and it startes fine now. My motor is very seasoned. It was made in 1966, is all original and has been used weekly during mowing season it's entire life. Check the fuel filter and make sure that fuel is flowing through it. Then try the hand trick. It is so simple, it seems silly, but if the motor starts, at least you have defined what the problem is and can fix it. Good luck.
Link to comment
Share on other sites

Commissioner
Thanks for all the responses. I'll certainly try the suggestions. Usually a little gas in the cylinder has worked for me but hey this one could be a little finicky and the needed vapor is not being produced. I'll see if the carb is spitting! Thanks, Wayne
Link to comment
Share on other sites

One other trick I've used is to blow in the gas tank. Just be sure to hold your breath til your away from the fumes when your done. Did it the 725 the other day cause it wouldn't fire with full choke, poped right off after presurizing the tank for a moment.. MPH
Link to comment
Share on other sites

Marty, that works pretty good. I actually witnessed that proceedure at the Rhinelander picnic last spring. Since then I've used it a few times myself (when no one's looking):) Steve
Link to comment
Share on other sites

If you are getting fuel replace the condeser. A bad condeser will throw the timing off or cause low spark voltage which sometimes will not fire a plug under compresion load. A rare occorance but I have seen several bad cond. causeing all kinds of skipping and loading problems
Link to comment
Share on other sites

Commissioner
Well there is a good flow to the carb. Stong spark with the current plug, less with another plug. Tried covering the air intake to the carb. Seemed to be getting a vapor out the exhaust while cranking so I assume it is getting gas. The gas is fresh. New points/condenser were supposenly put in when the recent engine work was done. Other than replacing them one at a time is there any simple observation/test that can be done to check them out? Thanks
Link to comment
Share on other sites

If the points make the plug fire they are good. As for the condenser, you can't tell unless you replace it.
Link to comment
Share on other sites

Hey no one is suppose to know about blowing in the tank.That is my secret.It does work on those wonderboys.Don't forget about how to load a tractor with the tiller on.Bob
Link to comment
Share on other sites

ka9bxg, your supposed to ride the tractor to till the garden. Not ride the trailer while your tilling the tractor.
Link to comment
Share on other sites

do u have enough compression?? is it possible one of the valves r not closing fully?? can the exhaust gases escape?? u need spark / fuel / and compression at tdc
Link to comment
Share on other sites

maxtorman1234
From having this same experience with my kohler, my carb was terribly plugged, and I had to close the points to about .015 instead of .020. The spark was strong, but it wasnt always continious. Eventually got the engine running with a different carb. Adjusted the valves a little, new points and condencer and now it runs great. DOnt know if this helps, but I thought i'd try:D
Link to comment
Share on other sites

Commissioner
I will be picking up a new condenser/points and giving that a shot but I haven't totally ruled out the carb yet. I welcome all suggestions.....experience is a great learning tool.
Link to comment
Share on other sites

Guest
This topic is now closed to further replies.
×
×
  • Create New...