18 hp Briggs opposed twin

rwise · Oct 1, 2005

model 422707 type 1522 01 code 9303055B The deal is it runs great until you shut it off. I can run it all day (as long as the gas holds out), turn it off and it will not restart! Pull the plugs and they have spark, I have changed the coil twice. Put a new set of plugs (briggs and straton) in it and it will start right up and run good until it is shut off, then it needs another new set of plugs. I have started using H10 plugs and they last about 4-6 starts, then needs a new set. Thanx Richard

Pony · Oct 1, 2005

Re: 18 hp Briggs opposed twin

Are the plugs fouling due to flooding?? My first instinct is to think that the needle valve in the carb or a gas logged float is causing the engine to run rich and foul the plugs on a restart. Have you looked at the carb at all? ...just seems like this is a fuel issue. my .02 cents.

dolluper · Oct 2, 2005

Re: 18 hp Briggs opposed twin

Do a compression check,maybe check the under seat kill switch

Pony · Oct 2, 2005

Re: 18 hp Briggs opposed twin

just wondering....how is it running when it is running? Is it good fuel?, whats the air filter look like? You prolly already tested those, but with briggs engines its usually pretty basic issues that create any problems

rwise · Oct 3, 2005

Re: 18 hp Briggs opposed twin

I have taken the carb apart and cleaned it checked the float etc. all looks well with it. the plugs have a small amount of carbon on them but are not wet with gas, but smell of gas. I have not done a compression check yet be cause when it starts (always starts right up with new plugs) it runs good, no smoke (black or other) has no gas smell when running. I have completely disconnected the kill circuit/s and still no change. I am thinking of putting a hotter set of plugs in it.

Grant S · Oct 3, 2005

Re: 18 hp Briggs opposed twin

I wonder if the hot engine has reduced valve clearances so they dont shut properly, causing loss of compression. Will it start with a shot of ether? if so, fuel delivery is the problem. Air filter OK?

rwise · Oct 4, 2005

Re: 18 hp Briggs opposed twin

No it will not ever restart with the same plugs, the only way to get it to start is by putting in new plugs, hot or cold. I have never seen anything like this, no wonder I got it for $40. air filter (paper) is clean, I have cleaned the foam filter. On other engines that used oil I would take the plugs out and clean then burn the oil from them put'em back in and use them. that will not work with theplugs from this engine, they're dead. They still spark out of the engine, but wont hit. it turns over plenty fast. I'm just out of ideas.

dolluper · Oct 4, 2005

Re: 18 hp Briggs opposed twin

The only thing that makes sence is your have replaced the coil twice,this makes me think your coil ground circuit is faulty .Still a compression check is a must or your guessing, if you have low but equal compression check the one way valve in breather for being faulty allowing air back out of crankcase

rwise · Oct 4, 2005

Re: 18 hp Briggs opposed twin

I replaced the coils before I new the plugs were the problem (symptom?). I'll do a compression check, but it may be a few days. (very busy right now liquidating the assets from a 24 year marriage) What should the compression be on this engine?

dolluper · Oct 5, 2005

Re: 18 hp Briggs opposed twin

Comp 150lbs new

rwise · Oct 6, 2005

Re: 18 hp Briggs opposed twin

thanx, I'll swing by my brothers and pick up his gauge, then wally world and get new plugs, and test it this weekend!

dolluper · Oct 6, 2005

Re: 18 hp Briggs opposed twin

You are using Champion RJ19LM's gapped at .030

Mark42 · Oct 6, 2005

Re: 18 hp Briggs opposed twin

Does it have spark at the wire when it won't start after shutdown?

rwise · Oct 6, 2005

Re: 18 hp Briggs opposed twin

mark42 yes it does have spark, even on the plugs, but just wont hit at all. dolluper the last plugs I put in were champion H10 I think, before that I was using Briggs and straton plugs. I try the rj19lm plugs and see what happens!

Mark42 · Oct 6, 2005

Re: 18 hp Briggs opposed twin

I think either 1) The spark is weak and blowing out when the motor is hot or leaking down plug cap.... or 2) It is too lean when hot to start. Have you tried cranking it with the choke full on then check the plugs to see if they are wet when it doesn't want to start? I have that engine on my Sears tractor and it was getting hard to start when hot. I put in new plugs, and also had to adjust the carb a tad richer. Now it runs nice. I have Champion plugs in there now that match spec.

rwise · Oct 7, 2005

Re: 18 hp Briggs opposed twin

Mark I have choked it until it was flooded trying to get it to start. It will not restart even after it cools down until the plugs are changed, then it starts like nothing ever happened. Mine is the "Sears" also, when it starts it runs great. I have tried to run it a little rich and a little lean just to see what would happen, still the same, once it stops starting change the plugs. I could not find the RJ19LM but did cross them to 868-1 (could not find them) and the fast start plugs 5861 and picked up two of them @ $2.50 each! I'll do the compression test tomorrow and post it here. I have thought of running a little seafoam through it to see what that may do.

dolluper · Oct 7, 2005

Re: 18 hp Briggs opposed twin

That's the right plug $0.25 more each than the RJ19LM in a pinch you can use J19LM

DJ · Oct 7, 2005

Re: 18 hp Briggs opposed twin

I've had two engines do the same thing. One was a Honda ATV-300 cc, and a John Deere-Kohler 14 HP. It helped either if I let it idle for a while before I shut it down. Either way, once and awhile either would backfire and that was the end of that plug. Those engines run so lean they are very hard on plugs. The only thing that helped was an extended idle before shut down.

rwise · Oct 9, 2005

Re: 18 hp Briggs opposed twin

ok just ran the compression 90 on both. seems a little low I think I'll run some seafoam through it and do the test again. DJ I do let it idle before shutdown, it's in the instructions on the dash to do so. dolluper it was more like $1.00 more each. but they had them. I'll take note of the other number! Off to the fair for now, got to have some time off!!!!

dolluper · Oct 9, 2005

Re: 18 hp Briggs opposed twin

Ah low eh check that one way valve in the breather make sure air isn't coming back out it

18 hp Briggs opposed twin

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