Export thread

Hello, thanks for any advice.

What is going on with my craftsman mower?

Clean Gas.
New Fuel Line.
New Plug (RJ19LM) could not source the RJ2YXLE that originally came in the mower, but I am getting a nice spark with screw driver test and a nice pop off the new plug...so spark is good.
The old carb looked great inside, but after cleaning I still couldn't get it to run so I replaced the carb.
I pulled the kill wire to inspect for any wore spots...all good. I cleaned the contact on the kill swith too.
The air cleaner is good enough for now.

I am about to pull the flywheel to look for a sheared keyway. I cannot image the governor arm has slipped...what am I missing?

Any ideas?

On briggs you don't have to pull the flywheel to check the key. Just remove the starter cup or what ever is above the flywheel, and you should be able to see if the key is square or has been offset or actually sheared. If sheared then you can pull the flywheel, and make sure to retorque to correct amount to prevent from possibly shearing the new key.

ILENGINE said:

On briggs you don't have to pull the flywheel to check the key. Just remove the starter cup or what ever is above the flywheel, and you should be able to see if the key is square or has been offset or actually sheared. If sheared then you can pull the flywheel, and make sure to retorque to correct amount to prevent from possibly shearing the new key.

Click to expand...

Thanks ILENGINE. I removed the starter cup and I was happy when I found the sheared key. Not so happy after I realized It was sheared badly and it put a pretty big burr on the tapered seat. I polished it out as best I dared and I had some replacement aluminum keyways from a couple of years ago when working on my lawn vac, but after replacing the keyway it still will not start?

Gap on the coil is approximately .008 to .009 my feeler gauge doesn't want to slip under very easy even at .008.

Do you know what the gap is on this motor I was guessing matchbook cover at about .012. If I'm remembering correctly it should be around .010 to .015 or so??? Why would the gap have shrunk?

A couple of pulls did act as though it was firing. In this humidity I'm running out of umphhh.

A business card will fit the bill.... I use my cards for the bigger Briggs like you got and my service tags for the smaller 3 HP engines..... My service tags are thinner 10 thousands and my cards are 13.........

Let us know Mon Ami ~!~!

BTW take coil off and then take a bastard file and lightly clean the mounting posts and then sand the mating surface on the coil......... You'll be glad you did...........

Thanks. I will try that...tomorrow. When I put the flywheel back on and tapped the keyway back in I was able to rotate the flywheel back and fourth a degree or two. I basically split the difference and called it good. I'm hoping I don't need a new flywheel. I will do what you mentioned to the coil posts and post the results.

I guess I shouldn't complain about humidity seeing where you are from.

It sure was miserable here today!

Well, I thank you for the advice, but it still will not start.

You know when a flywheel shears the key and the flywheel spins about 180 degrees out, where the carb blows and the exhaust sucks...it's doing that with the new keyway installed.

It doesn't backfire. It doesn't kickback. I don't know what the original owner did to have the keyway shear. The blades look good with no obvious bends or gouges.

I'll keep messing with it. It will eventually succum to the pressure or take flying lessons.

Any further suggestions?

Thanks.

Yes, you have a bad valve. Those symptoms you mentioned go straight to a valve issue............

Boudreaux In Eunice La. said:

Yes, you have a bad valve. Those symptoms you mentioned go straight to a valve issue............

Click to expand...

Boudreaux, I pulled the muffler and the emmisions cover. I know, I know, that doesn't mean the valve is seating properly or not cracked, but both valves do move freely. Is that why I am hearing a hissing sound when pulling the starter rope?

You know when a flywheel shears the key and the flywheel spins about 180 degrees out, where the carb blows and the exhaust sucks...

Click to expand...

Just to clarify...A sheared key would not do this.

Yes a hissing sound is a bad valve ...... Or one not seating well...... Can you borrow a leak down tester ???

That will tell the story all the way......

Sorry for the late response, I had to go pull a load of water melons from Sugar Town La. this afternoon....... Just got back from selling a few at Tractor Supply here in town ...............


Make sure the key didn't shear again...... That happened to me before..............

Let us know Mon Ami ~!~!

Boudreaux In Eunice La. said:

Yes a hissing sound is a bad valve ...... Or one not seating well...... Can you borrow a leak down tester ???

That will tell the story all the way......

Sorry for the late response, I had to go pull a load of water melons from Sugar Town La. this afternoon....... Just got back from selling a few at Tractor Supply here in town ...............


Make sure the key didn't shear again...... That happened to me before..............

Let us know Mon Ami ~!~!

Click to expand...

Boudreaux, the new key is still okay so I tore into it. I'm wondering if the intake wasn't seating properly like you said.
I could not spin either one by using my thumb. Do you know the valve clearance on this series motor? I think I found the info on Briggs and Stratton website, .005/.007 Intake .007/.009 Exhaust if this is right???

It's a 128MO2-0952-F1

I measured the gap at around .005 on each one before removing the valves. The intake was suprisingly galled looking on the stem, but polished up easily. The faces on both were dirty. Of course I cannot find my hand lapper... The exhaust has some play, but I have seen worse. I'll order a head gasket and lap the valves. I hope this gets it!

Yes those clearances you posted were correct.... Lap em up and then check the clearances.....

Let us know Mon Ami ~!~!

Boudreaux In Eunice La. said:

Yes those clearances you posted were correct.... Lap em up and then check the clearances.....

Let us know Mon Ami ~!~!

Click to expand...

Okay, waiting on the head gasket now.

Okay, first head gasket arrived and FedEX decided that fragile warnings on packages don't apply to them. So, the first gasket was folded in two and ruined. In the meantime I rechecked the valves, measured the new lapped seats at approximately .055 width on both intake and exhaust.

The exhaust guide is worn and should probably be replaced, but aghhhh, I've got briggs and strattons laying around here that are severly worn and start first pull. THIS MAKES NO SENSE!

Time for conspiracy theories. Is there anyway in hell that the cam has magically moved in relationship to the rest of the moving parts of this motor? NOTHING else makes sense. Is there anyway that the gears have moved??!! Does this cam have plastic gears? (Okay, in asking that question I looked on the Internet and I just found the problem with this motor) The cam is freekin plastic. Anyone know what part number I would need to replace this with an ALL METAL CAM?

Thanks.

The cam is freekin plastic.

Click to expand...

Is that the problem?
Plastic cams have been around for a couple decades now, so...nothing new here.
Other than the Honda OHC (GVC 190 etc.) series of engines, I have not seen a plastic camshaft fail.
Have never seen a B&S mill with a failed camshaft.

You need to stick with the 005 and 008 on those valves. and yes those cams gears can turn when hitting something hard... They are epoxied together............

Russ2251 said:

Is that the problem?
Plastic cams have been around for a couple decades now, so...nothing new here.
Other than the Honda OHC (GVC 190 etc.) series of engines, I have not seen a plastic camshaft fail.
Have never seen a B&S mill with a failed camshaft.

Click to expand...

Russ, the motor will not start. The keyway was sheared. I have now been through everything except the internals.

If it was a V8 I would check to make sure the distributor wasn't 180 out, so I started looking on the net. As of right now I found the exact lawn mower and his problem turned out to be a spun timing gear on the camshaft. Another had two lobes lined up when it twisted the plastic camshaft. Yet another had the gear spin in relation to the lobes. The more videos I watch, the more the plastic camshaft looks like the problem. I don't know much about these little motors as far as interchagable parts.

I don't know if it is the cam either, but I am about to find out. Do you know what cam part number will work?

Boudreaux In Eunice La. said:

You need to stick with the 005 and 008 on those valves. and yes those cams gears can turn when hitting something hard... They are epoxied together............

Click to expand...

Boudreaux, I did. I think you misread my post above. I did slightly clearance both valves as they were tight at .005

Do you know an interchange to get away from that style camshaft?

I figured I should respond back so if anyone is interesed in the future.

When I first looked inside, the cam looked good...it wasn't. While rotating the crankshaft by hand the cam lobes were not where they should be when opening the valves. I compared the replacement ebay $1.50 camshaft and it became obvious that the thin metal bracket pinned just under the gear was also suspiciously bent.

I installed the used camshaft, replaced the case gasket, and put a new bottom crankshaft seal in and reassembled everything.

My dad was over at the house and I tossed him the camshaft. I asked him, "What's wrong with that?" He said, "It's plastic" and tossed it back.

It ran first pull.

Thanks for everyone's input!