# Briggs and Stratten engine



## rickyjoseph701 (Oct 18, 2012)

I have a b &s engine model 10h902 type 0285 -e1 code 04051251 that will not fire. I checked for spark tonight (with tester) and not even a dim spark.The plug appeared to be new so I did not check the gap on it. What should the correct gap be /?/???


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## usmcgrunt (Sep 16, 2007)

The correct plug gap is .030.The correct spark plug,if using a Champion brand,is RJ19LM or J19LM if you can't get a resistor plug.Just because a spark plug looks new,doesn't mean it is good.Try another spark plug.Have you tried removing the black kill wire from the small tab on the coil and check for spark?If you remove the wire from the coil and the engine starts,you have a short to ground some where in that wire.Also,if the engine starts,be prepared to choke the carb or pull the plug wire off to stop the engine since the kill wire is disconnected.
Hope this helps.


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## rickyjoseph701 (Oct 18, 2012)

I had it running the other night, but when I tried last night, it wouldn't spark or anything. I will be buying and changing plugs later today. No, I never checked the black wire as of yet, will do so tonight also and will get back to you when I have done these things. Thanks for your help. I replaced the spark plug with a new one and I do have spark, but not fire.


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## rickyjoseph701 (Oct 18, 2012)

I replaced the spark plug with a new one and I do have spark, but no fire.


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## usmcgrunt (Sep 16, 2007)

When you say you have spark and no fire,do you mean the engine is not trying to start?Have you tried pouring a little gas in the spark plug hole and starting it?If it runs after priming it,you have a dirty carb in need of some cleaning and probably a diaphragm kit.Below are links to removing and rebuilding the carb.Many thanks to Geo for the well written instructions.

Removing Carb-
http://outdoorpowerinfo.com/repairs/briggs_10l900_carb.asp
Rebuilding Carb-
http://outdoorpowerinfo.com/repairs/briggs_pulsa-prime_carb.asp

Here are excellent verbal instructions from our own highly respected,Geogrubb.


You need to install a new diaphragm kit, it is Briggs part # 795083 or old # 495770 also Lowe's has a kit #5083 which has the same parts.

Here we go;
Remove air cleaner, there are 2 bolts that hold things together, one on the front of the tank 3/8" and one into the block 1/2", remove these bolts, now "slowly" slide the carb/tank off the intake tube and breather tube, now tilt the tank in to release the throttle linkage and waalaa the carb/tank is removed. Check the intake tube to see if the “O” ring seal and plastic retainer are still on the intake tube, if so remove them and re-install them into the carb. Remove the 5 screws from the carb/tank remove carb(don't loose the spring) now spray all holes, cracks and crevases in both the carb and tank surface with brake parts cleaner, remove the main screen(looks like a thimble) with a small screwdriver pry out the main jet(carefully) and clean it, reinstall the jet, it can be difficult some times to get it to snap back in place(I use the rounded end of a screwdriver handle). Remove and clean the fuel pickup stem. Clean any junk/rust from the tank. Install the diaphragm on the tank then the gasket(no goo or sealer) now carefully replace the carb(the spring will try to misalign the diaphragm), tighten all screws a little at a time so as not to crimp the diaphragm until they are all tight. Install the carb/tank in reverse order and you are done. If I missed something one of the real mechanics will correct me. Have a good one. Geo


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## rickyjoseph701 (Oct 18, 2012)

It doesn't sound as though it wants to start.
I am going to pour a little gas in to the plug hole and see what happens. When I started this , I removed the old gas from the tank and it looked like milk!!!!


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## usmcgrunt (Sep 16, 2007)

If it looked like milk,and this isn't a baby your working on,the carb will definitely need a good cleaning and rebuild OR replacement.


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## rickyjoseph701 (Oct 18, 2012)

I put some gas In the spark plug hole and nothing happened. It didn't sound as though it wanted to start, but I di get my exercise from pulling the starter rope. I was just wondering if the flywheel key could be sheared or if it is something else.. I have cleaned and soaked and cleaned the carb and tank until I am blue in the face. When I press the primer bulb, I can see and hear gas going into the carb.


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## usmcgrunt (Sep 16, 2007)

If the engine has been sitting unused for a long time,it could be a combination of many things.Did you do a compression or leak down test to determine if the valves and piston are sealing correctly? If the engine is on a lawn mower,did you check the blade for any deep gouges to indicate it hit something to possibly shear the flywheel key? When you put gas into the cylinder and it still wouldn't run,it indicates there are other things besides the carb that are not working correctly.If every thing else is correct ( compression - spark at the right time - and fuel delivery) (pouring a little gas in the cylinder) the engine should run a few seconds even if the carb was removed from the engine.


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## rickyjoseph701 (Oct 18, 2012)

What am I shooting for as far as compression should be??? The other night I noticed that the fuel intake tube was broken in 2 pieces, so I found one that matched and replaced it, and from that time on ,I have been unable to start this mower.Not sure if this adds anything to the equation but what do you think?


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## usmcgrunt (Sep 16, 2007)

I "think" the compression should be around 40 to 60 pounds because of the compression release on the cam shaft.The intake manifold would be a problem IF the gasket on the engine side or o-ring on the carb side were not sealing good.


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## rickyjoseph701 (Oct 18, 2012)

You mentioned a intake manifold gasket, I just looked at the broken one (that was broken) and I do not see a gasket on it. The book I have does not show or mention a gasket so what kind is it? I am going to go back to when I noticed it was broken and re trace my steps , hopefully that will get it started.


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## usmcgrunt (Sep 16, 2007)

You are correct,there is only an o-ring that seals the carb to the engine.I got confused (pretty common for me)when you said the fuel intake line and thought you meant a manifold.


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## rickyjoseph701 (Oct 18, 2012)

So , where do I start to look?


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## geogrubb (Jul 28, 2006)

rickyjoseph701 said:


> So , where do I start to look?


If you will go to post #5, Umcgrunt posted 2 links, in the second link it shows the "O" ring in the carb, if this "O" ring is missing the engine will not run. Have a good one. Geo


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## rickyjoseph701 (Oct 18, 2012)

Please see next post


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## rickyjoseph701 (Oct 18, 2012)

I have been working on this all afternoon and I am still not sure why it will not start or even fire.Is there any way to check the coil to see if it is good or not without having to connect it to the engine.???? I am thinking that it is either a coil, or a flywheel key , what does everyone else think? Am I heading in the right direction It is getting gas as the plug is wet with an odor of fuel 
I have also removed the fuel tank and carb and I do have the O ring and a plastic ring.


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## usmcgrunt (Sep 16, 2007)

If you haven't already done so,checking the fly wheel key should be next on the list.Remove the recoil assembly and starter cup to see if the key is sheared.If the key is bad,replace it with a genuine part and not a hardware store key.Did you remove the kill wire from the coil when checking for spark? There are testers for ignition coils,but are pretty expensive for the average person (me).If you have access to another working coil of the same type,replacing it will tell you if the old one is bad.


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## rickyjoseph701 (Oct 18, 2012)

Good news!!!!! I removed the kill wire from the coil (as you suggested the other day) and it fired right up. I had another wire from a similar coil so I hooked it up to the coil and sure enough , it started after a few pulls of the rope. Thank You all so much for staying with me on this project, I really do appreciate it.


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## usmcgrunt (Sep 16, 2007)

Great news,glad you found the problem and got it corrected.:thumbsup::thumbsup:


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## rickyjoseph701 (Oct 18, 2012)

Thanks!!! next up a Craftsman (Eager-1) 6.75hp with a Tecumseh engine, not sure what is wrong with that, but I am sure I can rely on this site to get me straightened out.


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## sidejobjon (Jun 3, 2010)

GEO,
I was reading this tread sounds like my Briggs lawn mower, until the part were his started pulling the black wire off coil. So if Rickys did not start by doing this , would changing the coil be next step?
Thanks SJJ


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## usmcgrunt (Sep 16, 2007)

sidejobjon said:


> GEO,
> I was reading this tread sounds like my Briggs lawn mower, until the part were his started pulling the black wire off coil. So if Rickys did not start by doing this , would changing the coil be next step?
> Thanks SJJ


If you are sure you have spark to your plug,then pulling the small ground wire off the coil will make no difference.This procedure just proves that the ground wire is shorted to ground some where else and causing a NO SPARK condition.If you post the numbers from your engine,we will know how to help you proceed.Will your engine start if a little gas is poured into the cylinder through the spark plug hole? We can also find you a service manual for your motor.


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## sidejobjon (Jun 3, 2010)

The Numbers are B&S 126T05-5856-B1. "only two years old electric start next door neigbor gave up on it"I also poured gas behind plug & nota. Also Tryed starting Fluid. I went to Lowes & bought one more Plug & Changed oil. Sad two say not much oil came out ,if this helps.
Thanks John F


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## usmcgrunt (Sep 16, 2007)

Hello John,the lack of oil may have caused enough wear of the cylinder wall or piston rings to create a low compression of the engine.Do you have a compression gage you can use to check what it shows? Unlike two cycle engines,a four cycle with low compression (up to a point) will normally still start but run poorly with little power.

You said you bought a new spark plug.Did you try holding the plug on the engine block and have some one try to start the engine while you observe if spark is present at the plug? 

All engines need compression,fuel and spark at the correct time to run.You have to confirm each necessity before moving on to the next possible problem.

Are you using the pull starter or the electric starter? If the battery is weak,it may not be spinning the engine fast enough to start it.

Unlike your neighbor,we won't give up trying to get it to run (with your help)
Here is a link to the correct service manual for your engine to help you along.

http://dl.dropbox.com/u/12502267/B&S Service Manuals/01_270962SingleCylinderLHead.pdf


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## sidejobjon (Jun 3, 2010)

GEO,
338 pages Manual lets do it.
I did check the compression, But my tester does not hold the pressure ," should it ?" it was 25 but each crank went down,did not build up at each crank ,did not have to release pressure at end. 
I did test the spark againest engine. Has spark felt like i got hit with a stun gun.
I did charge the battery for 8 hrs, looks like it was spinning strong . During testing & never went dead ,in fact felt like if i keep cranking would have to start.But it did not.
Good to here that it should still start. This unit iis only 2 years old i took motors out of peoples trash that i got started,20-30 years old. I thought i scored getting this.
Thanks John F


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## usmcgrunt (Sep 16, 2007)

The compression tester should hold pressure until YOU release it.Probably a bad Schrader valve on the tester.If you are only reading 25 psi,that's not a good number.Try to beg,borrow or steal (then return) another tester to confirm your readings.
Since you confirmed spark (ouch),that is one step out of the way.Look at the blade on the mower,do you see any large nicks in the blade? If you see any damage,the original owner may have hit an unmovable object and sheared the flywheel key and is throwing the timing off.I fixed a 6.75 hp Briggs a month ago with a sheared key from hitting a water shut off box and putting a 1/4" gash in the blade.


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## sidejobjon (Jun 3, 2010)

GEO,
No blade damage, Key also looks good. I will see what i can do for compresson test.
Thanks John F


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## sidejobjon (Jun 3, 2010)

ITs only going up to 25 psi should I play taps?
Thanks SJJ


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## usmcgrunt (Sep 16, 2007)

Don't give up yet! Pull the breather cover off and check the valve clearances for proper gap.Intake should be .005 to .007.Exhaust should be .007 to .009.
These measurements are in thousandths,not MM and performed on a cold engine.You may want to pull the cylinder head to see if one of the valves is stuck open.Since it was run while low on oil,a stuck valve or worse could be possible.Refer to section - 6 of the manual for valve and compression information.I'm not GEO,but thanks for the compliment.:thumbsup:


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## sidejobjon (Jun 3, 2010)

USMC,
Things are looking up intake some were between.005 and .006. Exhaust .007. Did pull head not stuck. Thanks for walking me threw.
John F


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## geogrubb (Jul 28, 2006)

sidejobjon, umcgrunt has forgot more than I will ever know, however, thanks anyway. Have a good one. Geo


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## sidejobjon (Jun 3, 2010)

I mostly on the slot car side of HT. But hit this when life gets in way & machines break you guys are like having someone in Garage with me walking threw. I just lost my life membership i paid a year & Hank said before year up if i pay 30 more become a life member. He not owner ht no more & nobody answering Are you guys having same problem here?
Thanks In advance
John F


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## sidejobjon (Jun 3, 2010)

sidejobjon said:


> USMC,
> Things are looking up intake some were between.005 and .006. Exhaust .007. Did pull head not stuck. Thanks for walking me threw.
> John F


What should i try next?
Thanks John F


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## usmcgrunt (Sep 16, 2007)

At this point a leak down test would be in order if the compression with a GOOD tester is only showing 25 psi.A leak down test would show leaking through the valves or worse case scenario,leaking past the piston rings.There are numerous instructions for building and using one on the Internet.Did you ever confirm if you have a strong spark? Keep asking questions and WE will try to keep answering.


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