TylerFrankel1
Well-Known Member
It does look like you needed 756-9978B just based off of visual inspection of the old pulley.
Engine Pulley Removal
- Thread starter CubCadet_Chris
- Start date
StarTech
Lawn Royalty
PN 756-9978B does not exist per my MTD database. Appears to be a typo of the number I posted.
CubCadet_Chris
Member
I ordered 756-0978B on ebay and got it today. Swapped it in the tractor and that fixed my problem!
I did this all at dusk and noticed flames coming out of my exhaust pipe. There is a internal ring built inside the muffler that has fallen down inside. So now the exhaust pipe is basically plummed to a open hole in the muffler. I guess its time for a new muffler too because I can see that making it too hot inside the engine area. Who knows maybe that is what lead to the head gasket failure.
I also need to fine tune the engine speed. It seems like it idles high. I was adjusting it by sound. Ill have to get a tach. What should the rabbit (fast) speed be at? I think idle should be at around 1200rpm.
I did this all at dusk and noticed flames coming out of my exhaust pipe. There is a internal ring built inside the muffler that has fallen down inside. So now the exhaust pipe is basically plummed to a open hole in the muffler. I guess its time for a new muffler too because I can see that making it too hot inside the engine area. Who knows maybe that is what lead to the head gasket failure.
I also need to fine tune the engine speed. It seems like it idles high. I was adjusting it by sound. Ill have to get a tach. What should the rabbit (fast) speed be at? I think idle should be at around 1200rpm.
TylerFrankel1
Well-Known Member
It could be causing an overheat but I've personally never heard of that problem. I'm not an expert there though. Probably wrongly on my part, I tend to leave rusted or damaged exhaust alone because I don't care enough about noise to justify the cost of a new part lol.
bertsmobile1
Lawn Royalty
Could be a few things
1) exhaust valve opening a touch too early ( cam out 1 tooth or lash too small )
2) rich mixture Check the spark plug for powdery black deposits ( soot )
3) spark timing a touch too ******** ( move the magneto closer to the flywheel ) ( check the flywheel key )
If it is an old muffler the internal baffels could be burned out allowing the exhaust to come out too fast .
In theory the charge should have fully burned by the time the exhaust valve opens.
In practice it does not happen and you generally get a 1/2" to 2" of flame coming out of the head .
Any more than that and something is wrong
Having said that I have worked on mowers where the muffler glows red hot in he daylight and been told by the owners not to worry about it it has always done that from new.
1) exhaust valve opening a touch too early ( cam out 1 tooth or lash too small )
2) rich mixture Check the spark plug for powdery black deposits ( soot )
3) spark timing a touch too ******** ( move the magneto closer to the flywheel ) ( check the flywheel key )
If it is an old muffler the internal baffels could be burned out allowing the exhaust to come out too fast .
In theory the charge should have fully burned by the time the exhaust valve opens.
In practice it does not happen and you generally get a 1/2" to 2" of flame coming out of the head .
Any more than that and something is wrong
Having said that I have worked on mowers where the muffler glows red hot in he daylight and been told by the owners not to worry about it it has always done that from new.
bertsmobile1
Lawn Royalty
High speed is around 3600 rpm +/- 200 rpm
There is no advantage making them rev faster all you do is use more fuel.
Too slow and you get a bad cut because the blade tips are traveling too slow
There is no advantage making them rev faster all you do is use more fuel.
Too slow and you get a bad cut because the blade tips are traveling too slow