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Discussion Starter · #1 ·
I could use some help with a b&s carburetor. Model 259707. My neighbor brought this over to get repaired. When cold the engine starts fine and runs for about 3-5 min. and then it starts to flood out. It eventually dies. The carb has been pulled and cleaned twice. The bowl float is plastic with no apparent holes. The needle seat has the Viton on the end. I screw the jet all the way in while it is running with no results. I am puzzled. Help me guys!
 

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Discussion Starter · #3 ·
Thanks Mark, I will try this. Very informative link. It is still strange that it runs great for a while before it acts up.
 

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Yeah, the only explanation for that I can think up would be the engine can handle a richer mixture cold compared to once it is warmed up. :dunno:
 

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Discussion Starter · #5 ·
Okay guys I completely went through the carb with the same results. Another thought I had would be the coil. I'm thinking that when the engine gets up to operating temp the coil starts losing juice. Is this possible and how do you ck them? I have a nice Fluke multimeter that I can use.
 

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Lets take a step back for a minute so as not to look over something simple. Are you sure it is flooding out rather then starving for fuel?

If you have not tried it already loosen the fuel cap when it starts to sputter and see if it comes back to life.

That little fuel tank vent blockage problem has stung me on two engines over the years. I did not learn my lesson to check that after the first time around. :bag:
 

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Discussion Starter · #7 ·
I run it with cap off, same problem. And when it starts to sputter there is gas coming up in the air cleaner box. As the engine dies more there is more gas and when it dies out it is instant and lots of gas is in box. Almost like it is losin fire and not burnin gas. I am so frustrated! I could own this tractor with the hours I have in it.I ohmed out the coil and I get the same reading cold or hot. So I think coil is ok. Is it possible it's a plug?
 

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I feel your pain. Going through the same problem with the onan. I just replaced the points and condenser now it will fire right up but when it warms up it starts to loose power and gas shooting everywhere. Not sure whats going on maybe the float is stuck not sure i think i will tear off the carb and do a complete cleanup. I noticed 2 of the 3 screws on top of the carb are stripped out so I will have to fix that. I just reset the valves maybe i didn't get them correct. Always do something your sure of then stuff happens and you start to second guess. The plugs I have on this particular engine are sealed plugs not sure how it works but when pulled out and held up away from being grounded they still spark something new to me. I did have a bit of a problem when adjusting the valves i use some paper shop cloth to plug the intake and exhaust holes so i wouldn't get anything down in the cylinder head, big blunder as i cranked the engine over some of it had pulled into the intake valve unknown to me. The first initial start up it started but ran so slow. I pulled a plug and holy crap there it was paper stuck and pulled into where the valve stem goes. I took at least 2 hours of my time picking it out through the spark plug hole with a little bent pick. I tried to suck as much as i could with a shop vac out of the cylinder head but by this time the little minuet pieces were saturated with gas . Once I started it up what was left burned and came out the exhaust needless to say there was ashes floating all over. Uff Dah. I will never make that mistake again.
 

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..So I think coil is ok. Is it possible it's a plug?
Plug is a lot cheaper to swap out if it ends up not solving the problem then the coil is. ;)

I would say it would be possible for it to be the plug. Have you tried pulling the plug right after it stalls out and checking the quality of spark? Stalling after heating up is one failure coils seem to have. Also I believe you have the electronic ignition on that which makes for an additional area of failure within the coil assembly. Without some special testing jig I think it is next to possible to prove out a coil problem much beyond checking spark quality. Thing is your meter is putting out only a few volts DC to measure it. During operation the insulation has to withstand several thousand volt pulse. So DC measurements only work up to a point detecting problems.

Edit: This might be a useful link for you to look at: http://www.briggsandstratton.com/us/en/support/faqs/ignition-system-theory-and-testing
 

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Discussion Starter · #10 ·
Tks fellas. I'm gonna change plug first and if that doesn't work I will try a coil. I have one on a 5 hp b&s that is good. That should work. Never noticed much difference on coils except maybe no. of cyls. and these are both singles. I hope one of these work.
 

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Discussion Starter · #11 ·
Okay, great news. I got engine runnin smooth. Took coil back off & cleaned up the round pickup. The engine would finally stay runnin. When it started to sputter I pinched off the fuel line and it would smooth out. I did this about 5 times with same result. So I changed out a carb float that appeared good and BINGO.We have a sweet runnin tractor now. Tks to anyone that replied.
 

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Discussion Starter · #14 ·
Electrical issues

I'm trying to get a Cub Cadet model 1641 to run. I've checked the 3 safety switches that I can find with a meter and all ckd out. I have lights. When I try to start it the solenoid clicks but no start. I can jump the solenoid leads and start it and it runs. As soon as I let off the brake pedal it quits. Is the solenoid part of the safety circuit?
 

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I'm thinking 4 safeties possible. Seat, brake, PTO switch or lever, reverse detect?


Letting off the brake killing engine, first thought is seat safety switch.
 

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I'm trying to get a Cub Cadet model 1641 to run. I've checked the 3 safety switches that I can find with a meter and all ckd out. I have lights. When I try to start it the solenoid clicks but no start. I can jump the solenoid leads and start it and it runs. As soon as I let off the brake pedal it quits. Is the solenoid part of the safety circuit?
if the solenoid clicks then the starter should be turning, one of your problems is your solenoid is bad.

the other problem as mark has already mentioned, its most likely the seat switch because when you let off the brake you are also shifting your weight on the seat. its a simple item so if this is your problem then see if the metal tap got bent. they should be open (not touching) when the seat is pressed down but touch when no weight is on the seat. you want the seat to lift a bit before they touch to avoid engine dying if you just move around on the seat, bend it if need be to get this result.
 
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