Lawn Tractor motor problems

dothepuff · #1 07-13-2020, 10:23 AM

Have a riding mower that I just can't keep running. Here's what I've done so far and now at a total loss in what to do next.

Mower was running this yr then died. Went through everything and ended up putting a new carb on it. Went to start it and just turned over and nothing. So took the valve cover off and found a rocker off the valve. So screwed around for a bit and seemed to get everything back in place and it seems to be working like the other one....SOOOOO here we go again tried to start it and no go, put fuel in the carb and it will run till it's gone. Carb bowl is full, have spark I'm at a loss now

. I don't have a valve spring tool to remove the valve to check it but it seems to be functioning like the other??

HELP

JDK71 · #2 07-13-2020, 10:43 AM

set valve gap to 4 thousand and try it sounds like valves are out

Dean2 · #3 07-13-2020, 11:05 AM

If the rocker came off the valve stem, just putting it back isn't going to solve the problem. You need to fix that issue properly for it to run well again.

MyAlberta · #4 07-13-2020, 11:08 AM

If it runs with a fuel charge, I wouldn’t be concerned about mechanical yet, although a compression test would be telling. I’d be checking fuel lines for cracks, and the tank vent for restriction. What does your spark plug say visually?

Big Grey Wolf · #5 07-13-2020, 11:38 AM

You obviously found problem when "rocker arm" off. Just as mentioned before set your valves to .005 and .007 otherwise will crank like a Ford truck and not start. PS contecting rod may be damaged, need replace, had this problem with my BS riding mower, $12 part, set valves on mine now runs like a clock.

dothepuff · #6 07-13-2020, 12:14 PM

Well...

Just tried it again and same scenario turns over like a ford but wont start

took fuel line off turned it over and shot fuel everywhere, so that part works.

Fuel lines are good, can't test compression as don't have one. plug is a little dark but can't get it to run long enough.

Connecting rod look fine and straight.

Like Dean2 said it might be a bigger problem since the rocker was off?

Could that valve be broken??

HunterDave · #7 07-13-2020, 12:20 PM

I'm glad that you started this thread. I just received a new carb that I have to put on and hopefully that solves the problem. If not, it'll probably go in to get repaired. I'm not sure that I want to be messing with the valves, etc.

204ruger · #8 07-13-2020, 12:42 PM

If your carb bowl is full then it’s getting fuel to there, but is that fuel getting into cylinder? Is your spark plug soaked in fuel if you were to pull it out after cranking and trying to start? If not could be main jet in carburetor is plugged, could be low compression and the sucking ability of the motor isn’t enough to get the fuel in from the bowl sucked up through the carb, could be valves aren’t opening enough, maybe one valve stuck slightly open that might explain rocker coming off.

tirebob · #9 07-13-2020, 01:08 PM

Sounds like fuel is not getting to the carb and not a problem downstream. Start simple. Check everything back from the fuel supply line back to the gas tank. Could it simply be plugged? Cracked fuel supply line messing with the draw?

Dean2 · #10 07-13-2020, 01:17 PM

Quote:

Originally Posted by tirebob

Sounds like fuel is not getting to the carb and not a problem downstream. Start simple. Check everything back from the fuel supply line back to the gas tank. Could it simply be plugged? Cracked fuel supply line messing with the draw?

Float bowl is full, gas is getting to Carb. The fact the rocker has come off the push rod says there is something wrong with that valve. No matter how loose the adjustment was, it should not be loose enough to fall off unless the set nut was completely off and the rocker could rotate up a long ways and even then it should usually not have enough lateral movement to come of the push rod.. Either the rocker assembly itself is broken allowing the rocker arm to move sideways or if that part is fine you need to pull the rods and the valve and see what is allowing so much lateral movement in the rocker arm that is is able to fall off the push rod. If the intake or exhaust valve is not opening properly the engine will not start.

MountainTi · #11 07-13-2020, 01:21 PM

Quote:

Originally Posted by dothepuff

Well...

Just tried it again and same scenario turns over like a ford but wont start

took fuel line off turned it over and shot fuel everywhere, so that part works.

Fuel lines are good, can't test compression as don't have one. plug is a little dark but can't get it to run long enough.

Connecting rod look fine and straight.

Like Dean2 said it might be a bigger problem since the rocker was off?

Could that valve be broken??

You mean pushrod I'm assuming?
If you had a broken valve it would make quite a racket bouncing off the top of the piston, most likely it wouldn't actually allow engine to turn over when it jammed in there

tirebob · #12 07-13-2020, 02:09 PM

Quote:

Originally Posted by Dean2

Float bowl is full, gas is getting to Carb. The fact the rocker has come off the push rod says there is something wrong with that valve. No matter how loose the adjustment was, it should not be loose enough to fall off unless the set nut was completely off and the rocker could rotate up a long ways and even then it should usually not have enough lateral movement to come of the push rod.. Either the rocker assembly itself is broken allowing the rocker arm to move sideways or if that part is fine you need to pull the rods and the valve and see what is allowing so much lateral movement in the rocker arm that is is able to fall off the push rod. If the intake or exhaust valve is not opening properly the engine will not start.

Yeah for sure the rocker is "an issue", but I am going by hthe OP saying it runs until the carb is drained of fuel. If it runs until the fuel is used then dies, sounds like fuel supply no? Maybe I am missing something?

Dean2 · #13 07-13-2020, 02:26 PM

Quote:

Originally Posted by tirebob

Yeah for sure the rocker is "an issue", but I am going by hthe OP saying it runs until the carb is drained of fuel. If it runs until the fuel is used then dies, sounds like fuel supply no? Maybe I am missing something?

It is possible that the carb isn't passing fuel from the bowl to the cylinder. Problem with squirting gas into the venturi is, even with valves that aren't working right you have so much fuel in the carb that you actually get some bypass into the cylinder. Most times I would agree with you and I would make sure the carb is working right first, but with the rocker issue, that is just too big n issue not to fix first. Even if there is a carb issue, that has to be fixed and any time I find that obvious a serious fault I always rectify that first even though I would not look at the valves as the first step normally.

JDK71 · #14 07-13-2020, 02:36 PM

i work on a lot of these just set the valves to 4 Thousand and see how it starts

pgavey · #15 07-13-2020, 02:41 PM

I'm with tire bob if it runs with gas in the carb it should run once you find the carb problem. Although the rocker is another problem Remove the carb bowl remove the low and main jet check with a light to see if they are plugged,use a strand of copper wire to clean out. The hole where the main jet screws in has a passage up into the carb throat, make sure this is not plugged also. The valves must be adjusted on the outer base circle of the cam, other words at the cam max lift. Hope this helps. Phil.

dothepuff · #16 07-13-2020, 03:20 PM

Thanks everyone for the input...but still no go

Done everything that was suggested and still wont run.

Went TDC, set valves to 40thou, checked fuel lines again all good and flowing, pulled new carb apart and blew everything out and can see light through all ports. Bowl is full but still doesn't seem to be getting fuel to the piston, if I dump fuel it runs for a few seconds then stops.

Only reason I pulled valve cover was a friends was doing the same and he had a stuck valve. Just remembered this, so when I pulled the cover that's when I seen the rocker was of the push rod, the lock nut and everything else looked in place and it was the intake side, when I loosened everything up to get it all back in place it seemed the spring was stuck, when I was turning the motor by hand to get things back in place there was a "snap" and it started to move freely again. It seems like something simple that I'm missing BUT I'm concerned about the rocker coming off the way it did.

My head hurts so I'm taking a break...

tri777 · #17 07-13-2020, 03:26 PM

Are you sure you don't have trace amounts of water in gas tank? I went through an
ordeal very similar to this last summer and water on bottom of tank was my issue.

HyperMOA · #18 07-13-2020, 03:36 PM

If you dropped a pushrod off of a rocker the engine stops then and there. (Unless it is a multiple cylinder engine, then it’s a dead miss) How much fuel you pour down its throat or sea foam you spray on the tires is not going to make an engine run without a functioning valve train. Sometimes if it’s an exhaust valve on a multi cylinder engine it’ll run but that cylinder ends up exhausting out your intake. Fairly distinct sound. You need to insure your valves are moving freely, that there is proper lift from the cam base circle and that lash is set correctly. One fella is saying 4 thou and you replied saying you set it to 40 thou. Is 40 thou the correct spec? Also make sure the pushrod is straight. Get your rockers rocking right and you’ll have a spare carb for parts.

JDK71 · #19 07-13-2020, 04:12 PM

.004 is what i set them at

dothepuff · #20 07-13-2020, 04:19 PM

My mistake on setting the valves. I did go and reset them at 4thou/.004. Still wont run but when I feed it fuel it seems to wanna run fine. Usually pretty good at solving these issues but this one is kicking my arse.

hawk-i · #21 07-13-2020, 05:27 PM

1) proper fuel
2) proper spark
3) proper timing
4) proper compression

and it will start and run great!

not hard to check 4 things....

dothepuff · #22 07-13-2020, 05:28 PM

OK...Went through it all again and still nothing, said F it and put the old carb back on and she fired right up

but still have no idea why she wont run with the new carb

....

Don't care anymore....wife is happy she can cut grass and I'm about to sit back with my own and try to unwind from this...

Thanks everyone!

HyperMOA · #23 07-13-2020, 09:54 PM

Quote:

Originally Posted by dothepuff

OK...Went through it all again and still nothing, said F it and put the old carb back on and she fired right up

but still have no idea why she wont run with the new carb

....

Don't care anymore....wife is happy she can cut grass and I'm about to sit back with my own and try to unwind from this...

Thanks everyone!

So you set the valves and have a spare carb? I believe it.

Now where did you get said carb? If from a dealer I’d be returning it as they obviously got you the wrong carb. If you’re gonna have a spare carb it should at least be a usable one. If you got it from some self-serve Chinese knock-off site, well it was always a gamble. 😀

dothepuff · #24 07-14-2020, 07:39 AM

Quote:

Originally Posted by HyperMOA

So you set the valves and have a spare carb? I believe it.

Now where did you get said carb? If from a dealer I’d be returning it as they obviously got you the wrong carb. If you’re gonna have a spare carb it should at least be a usable one. If you got it from some self-serve Chinese knock-off site, well it was always a gamble. 😀

Well they don't make this motor anymore and to find it was going to be more then the mower was worth, so had to go to Ebay to find it and I guess I got a quality Chinese knock off..

Big Grey Wolf · #25 07-14-2020, 09:34 AM

Boy, I am disappointed the AO mechanic team could not get this motor working, always thought we could solve any problem except perhaps corona.

58thecat · #26 07-14-2020, 10:21 AM

Quote:

Originally Posted by Big Grey Wolf

Boy, I am disappointed the AO mechanic team could not get this motor working, always thought we could solve any problem except perhaps corona.

corona goes good with grass cutting on a hot day....

dothepuff · #27 07-14-2020, 01:27 PM

Tried a few different things to see what the hell is going on....and from what I can tell it's the fuel solenoid on the new carb that's not working. Put the old one on and away she goes.

Dean2 · #28 07-14-2020, 02:02 PM

Quote:

Originally Posted by dothepuff

Tried a few different things to see what the hell is going on....and from what I can tell it's the fuel solenoid on the new carb that's not working. Put the old one on and away she goes.

If you bought if off Ebay or Amazon, send it back. I have got a couple of defective carbs over the past 5 years and got no arguments getting them to replace or refund. The last thing they want is bad reviews.