Mower won't run properly

[Natebearcat61]

I've had it with this mower. It is a old 90's craftsman riding lawn mower I got off a friend for free. The mower was sitting in his lawn for years so I asked and I received. I thought I would be a fun project but has turned into a nightmare. It has a 15hp Briggs ohv engine. When I first got it it didn't run but I put a new magnito and spark plug on it and it runs... But not very well. It will surge to high and low rpms. When too much throttle is applied or mower deck is activated it will start sputtering requiring me to disingage the mower deck and throttle down until it decides it wants to run again. I have cleaned carb very well, replaced oil, checked valves ... The whole nine yards but it still throws a fit and won't run... Someone please point me in the right direction

 

[Jack17]

Next...adjust governor.


BTW, post engine's #s

 

[KrashnKraka]

Next...adjust governor.


BTW, post engine's #s

Governor spring is dodgy.
Amounts to the same thing you point to but maybe worth
a look for the complete fix.

An oddball fault on these is the grounding wire for
shutdown, depending on which engine is being tinkered with
it may happen the grounding mechanism shorts to ground at revs.
Some ID would help, sure ;-)

KK

 

[Natebearcat61]

Governor spring is dodgy.
Amounts to the same thing you point to but maybe worth
a look for the complete fix.

An oddball fault on these is the grounding wire for
shutdown, depending on which engine is being tinkered with
it may happen the grounding mechanism shorts to ground at revs.
Some ID would help, sure ;-)

KK

I replaced the governor spring and now it dies because the governor over throttles and it dies. But the governor isn't the problem. To me it seems like a fuel problem but idk. If too much throttle of the mower deck is ingaged it will start sputtering and smoke will come out and it will die and the model for mower is 28n707
The engine model number is 917.252512

 

[shiftsuper175607]

I replaced the governor spring and now it dies because the governor over throttles and it dies. But the governor isn't the problem. To me it seems like a fuel problem but idk. If too much throttle of the mower deck is ingaged it will start sputtering and smoke will come out and it will die and the model for mower is 28n707
The engine model number is 917.252512

Are all the pulleys and idlers free spinning on the deck?
You may have a frozen bearing, causing the belt to smoke on the pulley...thus putting too much load on the engine.

You may have to remove the deck (simple job) and check everything out.

 

[KrashnKraka]

I replaced the governor spring and now it dies because the governor over throttles and it dies. But the governor isn't the problem. To me it seems like a fuel problem but idk. If too much throttle of the mower deck is ingaged it will start sputtering and smoke will come out and it will die and the model for mower is 28n707
The engine model number is 917.252512

Thanks... that engine info can be checked out.
I'ts only text noise but I am hearing you could check the air gap of newly fitted coil and the timing marks position.
Then get into the idle and fast run settings on carby... the "smoke" you are seeing is likely a flooded (fuel) chamber. Manuals for the model
should layout how to adjust the carby settings after timing and spark issues are resolved.

Cheers....
KK

 

[Natebearcat61]

Are all the pulleys and idlers free spinning on the deck?
You may have a frozen bearing, causing the belt to smoke on the pulley...thus putting too much load on the engine.

You may have to remove the deck (simple job) and check everything out.

Yes they are all free spinning the engine only dies when under load like high throttle or engaging the mower deck

 

[Natebearcat61]

Thanks... that engine info can be checked out.
I'ts only text noise but I am hearing you could check the air gap of newly fitted coil and the timing marks position.
Then get into the idle and fast run settings on carby... the "smoke" you are seeing is likely a flooded (fuel) chamber. Manuals for the model
should layout how to adjust the carby settings after timing and spark issues are resolved.

Cheers....
KK

So I adjusted valves with a feeler gage and adjusted the gap for the coil. I adjusted the carburetor mixture screw and it helped a little but when I manually open the throttle after a certain point the engine will start sputtering again and shaking a lot and I have to throttle down until the engine smooths out again. I noticed that on the part of the carb that you screw the float bowl on to there is a hole on the side where it looks like something should screw into, could that be a problem?

 

[KrashnKraka]

So I adjusted valves with a feeler gage and adjusted the gap for the coil. I adjusted the carburetor mixture screw and it helped a little but when I manually open the throttle after a certain point the engine will start sputtering again and shaking a lot and I have to throttle down until the engine smooths out again. I noticed that on the part of the carb that you screw the float bowl on to there is a hole on the side where it looks like something should screw into, could that be a problem?

Using a short length of maybe 3/16" nominal bore (ID) flex hose blow into that hole.
Any air entering the mix chamber after the meter device is going to screw over the engine operation. Find out if/where that hole leads to.
Sounds to me like there is a high speed problem with fuel or advancing the cam.
Man can fix that. Eyes and ears on, stay alert and
persistant ;-)

KK

 

[KrashnKraka]

Supplementry:
You do have the belts off engine pulley when doing your tests, hey?

KK