Snapper w Briggs & Stratton Intek V-twin engine trouble

[Lman 14]

Hi all, things were going reasonably okay for a year, until today. Snapper ELT2240RD, Briggs & Stratton Intek V-twin 725cm² 22HP sounding very rough on restart when hot, engine losing power every few seconds, accompanied a little puff of black smoke out the exhaust, Then refusal to start, turning over but engine does not fire. Oil changed, oil filter changed, air filter cleaned a month or two ago. Tried two new spark plugs today, machine started but they got black very quickly and are wet, gasoline. Refusal to start again, turning over but not firing. Might start again when engine cold and cylinders not flooded.

 

Some footage when the new spark plugs were just in, you can hear the engine struggling.

 

Phoned a mechanic, he will come and have a look next week. Not looking good, is it? Any ideas what I could try in the meantime to diagnose? Many thanks to the forum for providing the engine service manual here, Engine B & S Twin cylinder Intek OHV SM.pdf 1.0.0

 

 

 

 

Video_1.mov

Edited August 23, 2023 by Lman

[Gasaholic 224]

Sheared flywheel key, perhaps? Surprisingly common issue often overlooked on engines like that.  Could also have a failing coil or shorting wire, also check valve clearances and while covers off take a close look at valve guides. They are notorious for getting loose and shifting out of place, causing rockers to hang up and bend pushrods.  Also very common to have blown head gaskets. Lots of common problems with those briggs engines, really needs a step by step diagnostic series going back to the basics (Suck, Squeeze, Bang, Blow and all that.) You have service manual, which is an excellent place to start with (In other words RTFM)  Some stuff you'd need diagnostic tools which are not common to homeowner tool kits, but some are surprisingly cheap and very handy if you think you may do more than one engine diagnostic.  Simplest thing to do - Drain all the gas and put in fresh fuel - water in the gas could be one of multiple causes of your overall problems - May not be just any one thing wrong. 

 

[Lman 14]

Thank you, I looked at a few videos as well to get me going. Damage from overheating seems common with these air-cooled engines. Already found an issue with a valve guide that looks like it's come out a bit and has loosened a rocker, will check the other cylinder tomorrow when I've got more light. Pushrods appear ok, but I will have a better look.

 

Bottom rocker jiggles about a bit, top one feels solid. 

 

 

Update: I was wrong, there is a little play in the rockers when they are not pushing down the valve, of course. Other side looks fine as well. Rods are all in position and not bent. I can't see any guides that have come out either, but it's hard to see. I probably need to stuff a bit of rope through the spark plug hole to prevent the valves from falling out and take the springs off. It's been years since the clearance on those rockers has been adjusted, maybe that will help fix it?

 

No mice nests either, there's some crud there which I will try and clean off but not as much as I might have expected.

 

Edited August 24, 2023 by Lman

[Lman 14]

I cleaned the dirt off the outside of the cylinder heads, there wasn't all that much but perhaps enough to cause cooling issues. I was able to finish the mowing without any problems. I suppose the metal plates around the engine are there to better direct the cooling airflow from the flywheel fan, but the lesson learned is that fine fragments of dirt and grass can accumulate behind them. Hoping the issue will not reoccur and this thread might be useful for other owners of Briggs & Stratton V-twin engines.

 

Edited August 28, 2023 by Lman

[Lman 14]

Deleted, double

 

Edited August 28, 2023 by Lman

[RED-Z06 2,221]

Probably the carburetor flooding, they were not great carbs, lots of opportunities to let fuel where it shouldn't be

[peter lena 8,631]

@Lman been using this for years now , change in operational running ease , is very apparent ,https://www.walmart.com/ip/Rislone-Hy-per-Lube-Zinc-ZDDP-Supplement-11-oz/52628126?  you might also have other issues , but have this in all my small engine oils , pay attention to oil color , showing its working , cleaning , varnish removing . action . read bottle amounts , to oil , pete

[peter lena 8,631]

@Lman read the specs on that zinc , and its detailed varnish cutting ability , and the ENHANCED  REMOVAL OF CRUD , AT OIL DRAINAGE TIME . bottle specs are spot on 2 ounces for each QT , small measuring cup, rough neglected engines that I used this in , steadily went from a noisy smoker , to a non smoking , much smoother running engine . have had , zero / no related issues with this , another thing , is no consumption  of engine oil , was more than likely , ring  blow by varnish . I spend time on a recovered engine , in every area , after an initial fuel bowl clean out , a separate gallon of heavily treated fuel , do not scream it to recovery , listen to it , let it run at a  fast idle , once hot , drop the "  OIL " thats in it , 4 ounces of  zinc , 2QTS ROTELLA  30 WT  , + / - start up again and gain on where you  started . you might even start to see a reduction of the crap coming out of the exhaust .  my engines do not ,show any smoke at all , regularly  looked over for anything . make my changes to chronic problems ,  this works , pete