Export thread

7 HP Craftsman Model 917 370691 Front wheel drive walk behind self propelled mower.
B&S engine
Loses power on small inclines.
Runs great on flat surface or downhill. If I tip the front wheels up it starts to lose power with or without drive engaged.
Lift the rear wheels up it runs fine.
Cleaned the carb float bowl and venturi bolt. Nothing unusual found. Clean air filter. No fuel filter present on this model.
Fuel tank is full and oil is at correct level.
Carb float is hinged towards the rear of the mower.
Any suggestions appreciated.

Sure sounds like the incline is preventing fuel flow. Can you loosen the fuel cap temporarily and try? Might have to lower the gas level in the tank for this.

Cusser said:

Sure sounds like the incline is preventing fuel flow. Can you loosen the fuel cap temporarily and try? Might have to lower the gas level in the tank for this.

Click to expand...

tried your suggestion
no difference

It's a racing slick front wheel issue with no traction. Front wheel drive and slopes. Think about it.

Has nothing to do with losing power if the mower is fine on flat ground.

Front drives are horrible especially if you bag, gets even worse. Rear drive is where it's at.

juicer said:

with or without drive engaged.

Click to expand...

Ok reread what was stated. Shifting gears.

Look for low carb float level, gas cap trick or the like. Something limiting fuel flow at said angle. Fuel tank low in gas?

appreciate the eyes on.
gas full.
near instant response... raise front wheels runs like crap but is it fuel starved OR too rich???
tomorrow in daylight I will remove and clean the line from tank to carb. there is a dip in the line but you would think there is enough fuel in the float bowl itself to accommodate the tipping at least in the immediate response. I tried right after allowing the mower to sit (the bowl SHOULD be full) and immediately upon starting had the same response.
Replacement carbs are all of $8 but I am challenged by the WTF factor.
Thanks for playing along.

OK Took everything apart again to check the fuel lines and everything seems normal.
I am at a loss as to where to go next.

Fuel line partially blocked? Fuel line is too long and makes a big dip between tank and carb? I'd change the fuel line next - $1.50 a foot at auto parts store.

It is as short as it can be as it rounds the body of the mower from tank to carb. Ran a knotted rope through to make sure there wasn't any debris collected in a bend.\
As I noted previously, the response is instantaneous. i.e. as soon as I lift the front wheels off the ground (no self-propel engaged) it runs rough. Takes a second or two once I set it back level with the ground or lift the rear wheels to return to normal..

Does it blow any black smoke when it acts up?

Wonder if the ignition coil kill wire is grounding out at said angle?

Agree it shouldn't immediately die if you raise the front wheels. Bowl should have enough to run for 30 seconds or so.

I would remove the coil kill wire and see how she runs with her feet up.

Check to see if the plug is black. Choke plate might be sticking closed or partially closed.

Scrubcadet10 said:

Does it blow any black smoke when it acts up?

Click to expand...

No, but good question ie that would indicate running rich? so I guess I am back to gas starved...

slomo said:

Check to see if the plug is black. Choke plate might be sticking closed or partially closed.

Click to expand...

changed the plug as old one tip was nearly burnt off AND it was black
been running the new plug for a few days so can pull tomorrow and see its condition
dismantled the carb today and hosed everything in sight with carb cleaner
same as before

I am going back to Google noodling as I read somewhere a poster's Craftsman mower had a 22 degree limit on slope?? Can that be? My other 6.5 HP Craftsman self propelled does fine on the same inclines...
Mine doesn't seem to want to do a 15 degree slope.

juicer said:

No, but good question ie that would indicate running rich? so I guess I am back to gas starved...

Click to expand...

yes, black smoke is running too rich,

Scrubcadet10 said:

yes, black smoke is running too rich,

Click to expand...

ok so no black smoke so sounds like fuel starvation.
I've never had an issue with the coil kill switch and in fact can start the mower with the front wheels raised. I dismantled the carb today and removed the float pin and checked the seat and needle valve and sprayed it to hell and back with carb cleaner. Didn't dig any further into the carb as I don't have any gaskets etc on hand and anyways a complete new carb is only $8 delivered.
fuel line from tank to carb is fully patent and I dragged a knotted cord thru to be sure.

juicer said:

ok so no black smoke so sounds like fuel starvation.
I've never had an issue with the coil kill switch and in fact can start the mower with the front wheels raised. I dismantled the carb today and removed the float pin and checked the seat and needle valve and sprayed it to hell and back with carb cleaner. Didn't dig any further into the carb as I don't have any gaskets etc on hand and anyways a complete new carb is only $8 delivered.
fuel line from tank to carb is fully patent and I dragged a knotted cord thru to be sure.

Click to expand...

slomo said:

Wonder if the ignition coil kill wire is grounding out at said angle?

Agree it shouldn't immediately die if you raise the front wheels. Bowl should have enough to run for 30 seconds or so.

I would remove the coil kill wire and see how she runs with her feet up.

Click to expand...

Have you tried any of these yet?

only thing not tried was disconnecting the coil kill wire but with it connected I am able to start with the front wheels raised without difficulties.

juicer said:

only thing not tried was disconnecting the coil kill wire but with it connected I am able to start with the front wheels raised without difficulties.

Click to expand...

Okay but disconnect the kill wire and see for sure. Mow with it disconnected and raise the deck several times. Might be some bad insulation on the kill wire shorting out the coil when the deck is raised? Shot in the dark......

Kill wire disco'd, mower should run till the fuel tank is dry.

alright will do.
happened to have another same model carb/mower in my pile of junk (don't ask)
swapped the carb out and same symptoms persist
will try the coil kill with vice grips at the ready to either pull the plug wire or crimp the gas line

If solved, what was the reason/cause ???

Sorry. I had written the below post but never hit enter/save!
Fixed it! Slomo pointed me in the right direction if not the correct solution.
When I started looking into removing the shroud to access the coil kill wire (in the end, didn't actually remove the shroud) I noticed a bunch of grass stuck below the shroud.
Brought out the compressed air and blew what probably had been a mouse nest worth of crap out of there which apparently had been hindering the smooth operation of the auto choke!
Problem solved,
We now return you to your normally scheduled programming.

Thx.

juicer said:

Sorry. I had written the below post but never hit enter/save!
Fixed it! Slomo pointed me in the right direction if not the correct solution.
When I started looking into removing the shroud to access the coil kill wire (in the end, didn't actually remove the shroud) I noticed a bunch of grass stuck below the shroud.
Brought out the compressed air and blew what probably had been a mouse nest worth of crap out of there which apparently had been hindering the smooth operation of the auto choke!
Problem solved,
We now return you to your normally scheduled programming.

Click to expand...

You know what's coming next. Ready guys??

Remove the metal fan shroud. CLEAN that filthy engine to like new conditions. This is a YEARLY to-do in yours and every other mower engine manual. Behind the muffler and so on. Any oily dirt slime areas need to be gone. Those oil slicks insulate the aluminum retarding engine cooling. Neglect this and you are asking for engine damage.

Juicer had a mouse nest, juicer had a mouse nest. HA-HA!!! Glad she is a runner.

slomo said:

You know what's coming next. Ready guys??

Remove the metal fan shroud. CLEAN that filthy engine to like new conditions. This is a YEARLY to-do in yours and every other mower engine manual. Behind the muffler and so on. Any oily dirt slime areas need to be gone. Those oil slicks insulate the aluminum retarding engine cooling. Neglect this and you are asking for engine damage.

Juicer had a mouse nest, juicer had a mouse nest. HA-HA!!! Glad she is a runner.

Click to expand...

Oh great... brush my teeth once a month, floss once a year and now THIS!