Craftsman / Briggs 18HP Running on 1 cylinder

[jhwentworth]

Yes, you can hook this spark tester in series with the spark plug. Simply plug the tester into the plug wire and attach the clip to the spark plug tip. You will be giving the ignition a "double-jump" which should prove just how strong the spark is.

 

[Scooby074]

Yes, you can hook this spark tester in series with the spark plug. Simply plug the tester into the plug wire and attach the clip to the spark plug tip. You will be giving the ignition a "double-jump" which should prove just how strong the spark is.

Ill try that. I didnt think these small coils would have enough juice to jump two gaps

 

[Scooby074]

OK we now have SPARK~~!!!!

Im not sure what i did, but its working. I removed the flywheel to check the keyway and reinstalled, now theres spark.

Only thing i can figure is that the coil gap wasnt staying where i set it because one of the set screws was partially stripped (i didnt really catch this earlier).

I drilled and tapped for a larger screw, now its staying tight.

I bought some inline testers to confirm and all looks good!!!

THats the good news, heres the bad.,

The plugs are still fouling, and theres 1/4" of gas in the bottom of the intake.

THe RH plug is still getting warm and the LH is getting hot. I took some pictures to illustrate the fouling issue. THese were brand new plugs today.

The previous crack in the main jet housing has now turned into a chip missing. I used sealent on the threads, so i doubt theres gas getting by, but it doesnt look pretty.

I think the next thing im going to do is remove the muffler and check for any obstructions. Id like to change the carb out, but i really dont want to put any more money into this thing unless im sure it will fix it.

More pics can be found here :http://s650.photobucket.com/albums/uu221/scooby074/Briggs%20Problems/?albumview=grid

 

[Jimmy Joe]

Sure looks like you are getting way too much gas, if your choke is working properly and air filter clean I would take another look at that chip in the carb. Maybe some JB weld?

 

[jhwentworth]

Have you checked the needle in the carb? It looks like raw gas is being pulled into the intake. If the needle is failing, or misadjusted, the fuel level will be too high and cause a rich condition. A plugged atmospheric vent will also cause fuel to keep running into the carb.

 

[Scooby074]

Im going to JB weld in the Jet. This is the last kick at the can for the old girl.

Briggs online says that the original carb is no longer available. The current model replacement is $183 USD. Which will likely be 250 up here in canada. I think its getting to the point of cutting our losses. Too bad, the mower cuts great, even with the fouling plugs.

There was a new needle put in. The float was adjusted paralel to the carb. The fuel level in the last pic was the level when i pulled the top off the carb.

Ill have a look for a plugged vent.

Attached pic of fuel level.

 

[Jimmy Joe]

I was looking at your first picture of the carb bowl, you can see where the bolt head that holds in the jet. It looks like the bolt has a hole or something in the side of the hex head, is it a hole that could leak air or just cosmetic? I can't really tell.

 

[Scooby074]

The hex on the outside of the bowl is a bit chewed up but theres no leaks. Is that what your talking about? Or are we talking about the area behind the main jet?

today i took some JB weld and epoxied the jet in place and filled that chip in behind the main jet. This should prevent any fuel from passing the jet causing flooding.

If this works and the engine runs fine, i will consider a new carb. I dont want to throw a 200$ carb at a 23 year old machine unless im sure everything else is working.

Edit: Just got off the phone from sears. Carb is $232.99

 

[Scooby074]

No joy.JB welded main jet made no difference. Still flooding badly. 3/16" gas under the carb in the intake

Im going to check on a used carb tomorrow. If i cant find one reasonable, i think the old girls going up for sale.

 

[dfkrug]

Im going to check on a used carb tomorrow.

Sorry you are still struggling, Jason.

There are 2 used carbs for 18hp twins currently on Ebay. I don't know
if they are compatible with the older carbs from 16hp twins.

Anyway, there are tons of these lying around free, in the form of
derelict lawn tractors in people's back yards. That is how I got mine
(off a 79 Craftsman).

 

[Scooby074]

Sorry you are still struggling, Jason.

There are 2 used carbs for 18hp twins currently on Ebay. I don't know
if they are compatible with the older carbs from 16hp twins.

Anyway, there are tons of these lying around free, in the form of
derelict lawn tractors in people's back yards. That is how I got mine
(off a 79 Craftsman).

Thanks. I was looking at those. I sent some emails, they wont commit that theyre compatible with anything besides what they removed them off.

One was a 19.5 hp the other was a 16. Mines a 18hp. I THINK theyre compatable, but im not sure, I checked Briggs parts page, and neither ebay model crosses to my motor (at least that i can see). Plus ones alot newer than mine (96). I imagine the bodies are the same, but the jets would be different?

THe old girl is showing her age, but they really did make them better back then, Full welded frame, cast iron axle etc. And the rear discharge mows good ( maybe not as nice as a new full floating John deer).

Speaking of deer from my short time at the dealer, it looks like id have to go to at least a 300 series (maybe even a 500 series) to get a machine thats as heavy frame as the old craftsman/mtd. Is that correct? What models are recommended?

I have a place to check tomorrow that scraps mowers. Maybe ill get lucky.

 

[dfkrug]

I imagine the bodies are the same, but the jets would be different?

I would not worry about the jetting. Anything that will fit on your manifold,
or a manifold/carb setup that will fit on your block will be good enough.

The carb on mine has a brass float and, with a bit of cleaning, my old
engine started right up. It was rotting in a field for a dozen years.

I gave up lawns years ago, so I have no mowers.

 

[Scooby074]

I gave up lawns years ago, so I have no mowers.

THats the best advice yet

I found a carb for my mower today, $50. Not too bad, it was in pretty good shape. hope this fixes it. Guy offered to buy my machine for parts if i cant get it going (must be worth something, he said the deck is worth $$$).

Im going to clean and rebuild the carb, will post results.

 

[Scooby074]

Thanks to all who've helped. The old girl is working pretty good after a new (used) carb and a carb rebuild.

Comparing the 2 carbs, the jets in my old one were larger than my new one. I can only assume it was like that from years of being cleaned incorrectly.

Still the odd puff of black, but i figure thats from all the carbon that likely is on the cylinder head and piston. Plugs are nowhere near as fouled as when i started this adventure

Thanks again.

 

[Backman]

I noticed on this forum some talk about a motor running backwards:

I've got 18hp twin briggs that runs backwards. Initially it ran backwards when first started it up. I adjusted the ignition gap and it ran normal for a little while. Then it switched to backwards again and has been backwards ever since.

Things I did before starting it up: (1) new stator, (2) full carb clean (3) new flywheel key, (4) new spark plugs, (5) new oil.

I am having trouble torquing down the flywheel nut. I've heard it needs 145 ft-lbs. (is this right?) I can't lock the engine to get the torque on it. I already bent a belt pulley when I was using a belt and vice-grips to stop the engine so I could tighten it up. Any advice about how to lock this engine so I can tighten that flywheel nut? Does anyone know why this motor runs backwards and how I can fix this?

Thanks,
Backman

 

[Scooby074]

I noticed on this forum some talk about a motor running backwards:

I've got 18hp twin briggs that runs backwards. Initially it ran backwards when first started it up. I adjusted the ignition gap and it ran normal for a little while. Then it switched to backwards again and has been backwards ever since.

Things I did before starting it up: (1) new stator, (2) full carb clean (3) new flywheel key, (4) new spark plugs, (5) new oil.

I am having trouble torquing down the flywheel nut. I've heard it needs 145 ft-lbs. (is this right?) I can't lock the engine to get the torque on it. I already bent a belt pulley when I was using a belt and vice-grips to stop the engine so I could tighten it up. Any advice about how to lock this engine so I can tighten that flywheel nut? Does anyone know why this motor runs backwards and how I can fix this?

Thanks,
Backman

Hi , please see your other thread. I posted a answer there.