Ive got what used to be an 11 horse briggs on my old lawn tractor pulling snow blower duty right now. Ive increased the compresion probably @ 3 pts and can only run premium in it now. any way it was pinging BAD tonight. So I reached down and opened the jet some to the point where it was starting to smoke(black) the ping went away. My question is would a colder plug rectify my ping? do they even make them? or should I dump masive amounts of Isopropanol in the fuel. Did I miss another option? Thanks p.s. We had a pretty bad storm @6" of snow mixed with 2"rain and ice. it was throwing that wet heavy **** higher than my roof 10+ft and 20 ft'out. so I was working the snot out of it
Buy better fuel, is the easy answer. How much ignition advance are you running ? And what is Isopropanol ? Sounds like Alcohol.
It almost sounds like you have too high a compression.How did you increase it?Milled head?Thinner head gaskets? As there is no practical way to alter the timing on those engines(at least none that I know of)this could be a problem.Do you get any "run on"when you shut it down?Wondering if there may be some carbon deposits causing the problem. I hesitate to recommend this but on regular automobile engines that had an excess carbon buildup,a friend of mine used to use this procedure with excellent results: He would warm the engine up and then run it up to about 3,000 rpm and with the air filter removed take a coffee cup filled with a 50/50 mix of water and antifreeze,VERY SLOWLY pour the mixture into the carburetor ;decreasing it when the rpm fell off until the cup was empty.He did this with the exhaust pointing OUT of the garage as there was a considerable white cloud of smoke emitted from doing this. It would definitely clean out any carbon build up in the combustion chambers but you had to be careful because if it stalled out more than likely you would bend a connecting rod.
Isopropanol is Isopropyl alcohol (rubbing alchol). It's used in fuel to "dry" it. It doesn't remove water from gas, just makes it soluble in the fuel so it won't pool and freeze. I've heard that too large of quan***y of the stuff can burn valves and pistons. The type of explosion is hard on equipment like engine (http://en.wikipedia.org/wiki/Deflagration) But maybe some chemists on here can correct me on that. The B and S engines are very inefficient with intake and exhaust methods. Plug choice can make a big difference as far as temp. and power... like any engine... but worse in an inefficient one. Timing is a ****** to adjust in a lot of the older engines. Many have no adjustment at all unless you have machinist skills. Also check your points and condenser. And some B and S engine mechanics might correct me on this stuff too. Good luck with the snow.
Holy quick answers. The timing is what ever it is stock?? I dont know its fixed. and yes isopropanol is a type of alcahol. I think its a cross of Ethanol and rubbing alcahol. and also yes the head is decked and the block milled a total of .100. Its got more power now at half throttle than it did at full throttle before Mabey I did take it a little to far?? Yeah mabey Ill take the can and fill it with some 110 Ill bet it would like some lead again anyways. I didnt want too because its $5.60/gal. but, thinking its a mower how much gas can it use. Ill try that first... thanks
If its an overhead valve engine, reset the valves @ 6 thousands, also mix Sea Foam with your gas. Walmart sells it. Get the pour in kind not the aerosol
I'm not familiar with this exact product. Obviously you are or you wouldn't have recommended it Has it worked as good as they claim on their site? I know there is no such thing as mechanic in a can but some products do work. Thanks....
a cam change would probably fix it if such a thing exists. ive heard of guys brazing the lobes and hand filing but thats not rcommended. what about water injection ala i-v drip to the intake? you could use a gas tank valve to dial in the amount delivered.
We use it in our shop. Yes, we have an Outdoor Power Equipment business if you were wondering. Have always had good luck with it. Even use it in shop truck.
You need a lot more Alcohol,compared to gasoline. Methanol is around 2:1,Ethanol is around 1.6:1. Without increasing the jet size,you risk running very lean by dumping a bunch of Alcohol in the tank. The upside,is Alcohol likes more compression. The downside,is Alcohol doesn't like real cold weather, and can be corrosive on some metals. E85 is 85% Ethanol in summer,the % changes as the weather gets colder. Take a look at Propane.Not sure how it likes the cold. But it does like compression.
Propane behaves well in the cold so long as you aint using a huge amount of CFMs... the smaller the tank, the less CFM you can get away with due to evaporative freezing inside the tank resulting in pressure loss. no, it doesnt actually "freeze" but it does get a lot colder causing the liquid to contract (ever used a propane heater in winter and have the outside of the tank get frosty and loss of volume of flame/fuel? same **** here)... but, with an 11hp briggs, i cant imagine that thing using more than maybe, 80-90 CFM give or take, so a small (20# cylinder) shouldnt be a problem
quickest, simplest and most correct answer. also, you could try to find a stock head to put back on it. 100 thou is crazy. I'm amazed you aren't banging the valves off the head. if it's a flathead type motor, the combustion chamber can't handle that much added compression.
Wow, this takes me back to my first hot rod... a 2.5HP Te***pseh powered mini-bike (the little ****** that broke my foot!). I'd try draining your tank and seeing if that was the problem; sometimes a station has a bad load of fuel, and it just doesn't burn well. Rule that out, then put me in line with the "replace the cylinder head" crowd. -bill
You have some ideas to try so why not some more. All I know is when I increase compression I sometimes need to back up the timing. I have a 11 hp Briggs and might try this., Make a special flywheel to crank key, move the coil or decrease the point gap. My 11 hp has a counter balance system that I believe does not like higher than stock RPM. The flywheel key made from soft material might be the easiest.
Its nice to see that everyone has the Christmas spirit. Just last week you would have bashed this poor guy into next week.
FWIW, there are some "aftermarket" cams available for B & S engines, as well as hotter "factory" cams....used for karting, Jr. dragster, etc. They aren't particularly cheap, though. I have seen welded stock cams...couldn't say how long they would last...
Isopropyl alcohol does NOT contain 30% water (not sure where that # came from). It is rubbing alcohol. It is first cousin to methanol and ethanol. My advice would be add 1 0r 2 more head gaskets, switch to E85 and re-jet 30% larger.
take the 4 bolts out that hold it on to the snow blower. grab the engine around the exhaust pipe and the carb. (with gloves on) pull up fermly on the engine until it comes loose of the mounts. swiftly turn and fling the ******* into the snow bank you just made the other day. reach into your wallet and go to the small engine store and buy you a new B&S engine.
Throw a splash of tolulene in the tank before you go tearing the motor down. Tolulene is in the paint thinner aisle, and it's a good cheap octane booster. ~Scotch~
Well, keep tinkering. We got a small b&s to run nitro (without any load on the motor) so you should be able to deal with the compression. Dig around for a Jr Dragster board, those guys are building some ridiculous motors, as odd as it is.
Stock Briggs style head gaskets are .039 to .041 compressed. Just keep adding back gaskets til you solve the problem. And by decking the block and shaving the head youre killing the breathing for higher RPM's, that's more important than compression on those things. Frank
I can't tell you much w/o the model # of the engine. DON'T run 110 octane. I know others might tell you different, but without a sleeved engine you can melt it down. I have seen it happen. Flathead valves are set at .005-.007 on the intake, .007-.009 on the exh. OHV stuff varies from .002-.005 Int, .004-.007 Exh. You can do some adj. to the timing. The nominal gap on the mag is .010. If you add a slightly wider gap it will change the timing. I don't know if it has electronic or points. Prior to 1982 everything was points, most everything after is electronic. Points can be played with a little on these, nominal is .020. Good luck with this. Oh, BTW, I own a small engine repair shop, and B/S certified.
I didnt I decked the Head and milled the block. leaving the valves popped up higher in the head. I have a feeeling that the 110 gas will do the trick, I also like the propane idea. I have been mowwing with it all summer with out a problem. but with a TON more torque. Night and Day difference. I also made and adjustable GOV rod. WOT is Im guessing 2O00-2500 rpm with a ton of throttle angle left for bog down. I really like the improvement. and Like I said it pinged while I was working the snot out of it. WOT and @ 750 RPM drop. I am happy enough with the results thus far, that Id put this 11 HP tractor aganst any modern 16HP Tractor. Ill out mow it or snow blow it. The fact that this is the first time since first doing the motor that I had Audiable ping. means Ive got the tune close. I was just looking for that little better tune /saftey zone. Im a newb to the site so forgive me if im DEAD wrong but coments like this. makes me think some people have Crate engines in there car. Thats not hot rodding...... thats wannabe hot rodding. IMHO..... I cant leave anything alone. Everything I own is modified to some extent. any true hot rodder CAN'T tell me the only thing they own that is modified in any way is there car. if it is your living a lie. next snow fall Ill post how the fuel works Thank you for the replies. theres some damn good Ideas out there OK flame away
. . . GREAT tip! just care full how much you add (as stated by unkl ian, 20% is good.) jist remember, no smokin around the stuff, and for sure MIX THE **** OUTSIDE!!! do NOT ... repeat do NOT just add a bit to the tank, specially if the friggin thing is HOT. (please, dont ask me how i know this... just remember, eyebrows grow back in about two-three weeks, but eyeballs dont)
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