old belt drive snapper pro bogs engine when deck engaged

rvrepairlord

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  • / old belt drive snapper pro bogs engine when deck engaged
Hello, I have an older snapper pro, pistol grip, gear drive (belt drive), walk behind mower model # SPP140KW, i believe the deck size to be a 48" that i only use to mow my small yard. Previous to my ownership i believe the mower was given a Kawasaki 15hp repower, engine model (FH430V) which is a little apprehensive to start when cold, but seems to run like a scalded dog, with no smoke, no hiccups. The issue is this, when the blades are engaged, with engine at full throttle, the engine falls on its face, and drops down to what seems to be half throttle at best (with or without grass under the deck). It is usable in this state, but just barely due to the lack of power. The very second the blades are disengaged the engine jumps right back up to full throttle (blades still spinning to a stop). It is also notable that when in transit, with blades disengaged, there is no fluctuation in throttle or power, regardless of the drive gear chosen, hi or low. ??What could be the cause of this "bogging" for lack of a better word, when the blades are engaged?? It makes for really slow going when the grass gets tall. The blades seem to spin freely and are not making contact with the deck or any other visible components, they are also not shaped like boomerangs, nor appear as though they have eaten a cinder block. The spindles, though definitely not new by any means, nor silky smooth, also seem to have no major hang ups or notable failure, and to me, do not seem to be making any out of the ordinary noise. The mower is greased well, and new deck belts were installed last season. the only other notable issue is that the throttle cable was never hooked up, at least functionally, to the Kawasaki, so revs must be manually adjusted at the intake/carb linkage. (i have also bypassed the pistol grip safety switches)
This mower appears to be a ghost, like snapper tried to wipe its existence off the map. there are parts diagrams out there but little else. Though this turd is in rough shape, it is functional (mostly lol), was next to free, and lays nice stripes, id really like not, to have to replace it. !!What do you think? Pto clutch? Any ideas or info would be greatly appreciated!!!
 

ken2

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  • / old belt drive snapper pro bogs engine when deck engaged
Remove the spark plug wires one at a time. I bet you find one cylinder to be dead.
 

slomo

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  • / old belt drive snapper pro bogs engine when deck engaged
Fuel delivery, dead cylinder, valves out of wack, weak ignition coil or plug and dirty carb.

15hp on a 48" deck sounds rather low in hp. My 33" Snapper RER has a 14.5hp Briggs.
 

sgkent

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  • / old belt drive snapper pro bogs engine when deck engaged
also what engages the blades, a mechanical system, or an electrical clutch?
 

slomo

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  • / old belt drive snapper pro bogs engine when deck engaged
also what engages the blades, a mechanical system, or an electrical clutch?
Not familiar with that mower. Look for your mower manual online.



 

bertsmobile1

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  • / old belt drive snapper pro bogs engine when deck engaged
Fuel delivery, dead cylinder, valves out of wack, weak ignition coil or plug and dirty carb.

15hp on a 48" deck sounds rather low in hp. My 33" Snapper RER has a 14.5hp Briggs.
Not for a walk behind or for that matter an old fully mechanical drive ride on
It is hydros that gobble up fuel
 

bertsmobile1

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  • / old belt drive snapper pro bogs engine when deck engaged
Hello, I have an older snapper pro, pistol grip, gear drive (belt drive), walk behind mower model # SPP140KW, i believe the deck size to be a 48" that i only use to mow my small yard. Previous to my ownership i believe the mower was given a Kawasaki 15hp repower, engine model (FH430V) which is a little apprehensive to start when cold, but seems to run like a scalded dog, with no smoke, no hiccups. The issue is this, when the blades are engaged, with engine at full throttle, the engine falls on its face, and drops down to what seems to be half throttle at best (with or without grass under the deck). It is usable in this state, but just barely due to the lack of power. The very second the blades are disengaged the engine jumps right back up to full throttle (blades still spinning to a stop). It is also notable that when in transit, with blades disengaged, there is no fluctuation in throttle or power, regardless of the drive gear chosen, hi or low. ??What could be the cause of this "bogging" for lack of a better word, when the blades are engaged?? It makes for really slow going when the grass gets tall. The blades seem to spin freely and are not making contact with the deck or any other visible components, they are also not shaped like boomerangs, nor appear as though they have eaten a cinder block. The spindles, though definitely not new by any means, nor silky smooth, also seem to have no major hang ups or notable failure, and to me, do not seem to be making any out of the ordinary noise. The mower is greased well, and new deck belts were installed last season. the only other notable issue is that the throttle cable was never hooked up, at least functionally, to the Kawasaki, so revs must be manually adjusted at the intake/carb linkage. (i have also bypassed the pistol grip safety switches)
This mower appears to be a ghost, like snapper tried to wipe its existence off the map. there are parts diagrams out there but little else. Though this turd is in rough shape, it is functional (mostly lol), was next to free, and lays nice stripes, id really like not, to have to replace it. !!What do you think? Pto clutch? Any ideas or info would be greatly appreciated!!!
First things first.
When you apply a heavy load and the engine revs drop, the governor should relax and allow the throttle to open up wider to provide more power .
So firstly we need to know if this is happening .
We need you to watch the governor arm and see if it is moving in the open direction when you engage the blades.
Then we need to know if you can manually move the governor arm with your finger while the blades are on and the engine responds by spinning up to full speed.
You will probably need a helper to do this and be very very very careful where you put your hands & feet lest your snapper bite .
If the mower responds quickly then the governor is out of adjustment.
If the engine responds very slowly check for a heavy load by turning off the mower and trying to spin the blades by hand
They should spin easily without any sounds or binding.


If the governor appears to be functioning properly then try removing a plug lead alternatively on each side
If it runs fine one side & not on the other then as Star & Slowy mentioned you have a bad cylinder
This can be electrical or mechanical so the next step is to remove the kill wires & try the plug lead test again.
If it fails you can swap the coils, if the problem changes sides then that coil is bad
If it stays the same then it is mechanical & you will need to pull the rocker covers off to check the valve operation
 
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