Mcculloch 797, Super 797 thread

[heimannm]

A bad primer should not have that affect on the saw. If it has been setting for a while the metering diaphragm and/or fuel pump diaphragms may be stiff (ol' Vinny describes it as "hard as woodpecker lips") and not moving enough fuel.

It is possible to revive the old primers but it takes a bit of work. I don't remember if it was here on OPE or over on AS I posted some photos of the process.

Mark

 

[heimannm]

https://www.arboristsite.com/threads/mcculloch-carburetors.122113/page-8

 

[Lee H]

If it were me i would convert the flatback to a Tilly Hl series like a HL103, HL63

 

[Stihlalltheway]

A bad primer should not have that affect on the saw. If it has been setting for a while the metering diaphragm and/or fuel pump diaphragms may be stiff (ol' Vinny describes it as "hard as woodpecker lips") and not moving enough fuel.

It is possible to revive the old primers but it takes a bit of work. I don't remember if it was here on OPE or over on AS I posted some photos of the process.

Mark

Thank you, all great info and very helpful.

If it were me i would convert the flatback to a Tilly Hl series like a HL103, HL63

If I decide to go this route, is it a direct swap? If not, what needs to be changed? Thanks again everybody

 

[Bigmac]

It’s a pretty direct swap depending on the carb, you have to tweak things a little bit here and there to get things to work. And it’s very doable. My biggest complaint, you have manually Hold down the choke to get it to work, so I hit it with prime, from a bottle.
With a prime they fire right off. An sp125 with an sdc20, is a different story, they start great, but they also have a high idle detent and a choke that stays closed.

 

[Sloa]

moving along with my super 797, recently received new crank from Terry Ives. Will also order con bolts and new reed. Can I ask do I leave clutch key in or out. When disassembled clutch frozen but no indication of stress at that spot upon removal.

 

[jacob j.]

You can run it with or without the key, it doesn't make a ton of difference. I leave them out and then lap the clutch to the crank and call it good.

 

[Sloa]

Spark plugs, two tall ones(795,1-76) short one off the 797. It had spark way back in September. Is there any pitfalls in replacing. Is a spark plug just a spark plug. Would there be a resource for the little cup oil ring for the manual oiler. I’ve got two ,one is rock hard the other is half chewed. Or a work around that doesn’t bind.

 

[Sloa]

You can run it with or without the key, it doesn't make a ton of difference. I leave them out and then lap the clutch to the crank and call it good.

Thanks. Will leave in.

 

[Sloa]

Spark plugs, two tall ones(795,1-76) short one off the 797. It had spark way back in September. Is there any pitfalls in replacing. Is a spark plug just a spark plug. Would there be a resource for the little cup oil ring for the manual oiler. I’ve got two ,one is rock hard the other is half chewed. Or a work around that doesn’t bind.

Asking wrong sorry. Is there any reason to obtain oem spark plug or purchase modern cross referenced replacement. Any pitfalls

 

[heimannm]

I think you will find it is easier to install and disconnect the spark plug wire with the original type longer plug.

All of the IPL's that I looked at just call out an o-ring, 103198 but I don't have a reference for a standard size to replace it.

Mark

 

[Sloa]

I think you will find it is easier to install and disconnect the spark plug wire with the original type longer plug.

All of the IPL's that I looked at just call out an o-ring, 103198 but I don't have a reference for a standard size to replace it.

Mark

will try right now and see how it allows closure of cylinder shroud. No will not close and that’s with boot not attached.small stemmed profile definitely, no issues. Really enjoyed your series on the flat back carburetor.

 

[Bigmac]

I think you will find it is easier to install and disconnect the spark plug wire with the original type longer plug.

All of the IPL's that I looked at just call out an o-ring, 103198 but I don't have a reference for a standard size to replace it.

Mark

I think he is looking for 57736, the dust seal in the block. I don’t know of a replacement, it’s just a dust seal, I would either lube the hard seal with stp and run it or the if it’s resonable, have seen lots of kart saws that never had the seal. I always run one.

 

[Bigmac]

will try right now and see how it allows closure of cylinder shroud. No will not close and that’s with boot not attached.small stemmed profile definitely, no issues. Really enjoyed your series on the flat back carburetor.

I always run the short plugs in saw blocks, I have had the same issue, it depends on the coil and lead if it’s original too. The kart motors, that need a 1/2 reach, I haven’t found a short plug to have the correct reach. Imho the kart head with 1/2 reach need kart shrouds and deep boot cover

 

[heimannm]

Thanks Nate, now I understand...looks like I'm down to one felt and a couple of rubber seals (57736). I would guess a clever fellow could find a grommet that would fit and work.

Mark

 

[jacob j.]

I think he is looking for 57736, the dust seal in the block. I don’t know of a replacement, it’s just a dust seal, I would either lube the hard seal with stp and run it or the if it’s resonable, have seen lots of kart saws that never had the seal. I always run one.

Thanks Nate, now I understand...looks like I'm down to one felt and a couple of rubber seals (57736). I would guess a clever fellow could find a grommet that would fit and work.

Mark

There's probably a size of o-ring that would work too.

 

[Bigmac]

There's probably a size of o-ring that would work too.

Yes, thinking a about it now I bet there is a valve stem seal out there that Might work too

 

[Sloa]

New to me 6-10. Surprised that both saws share spark plug. Was in big city and spent time looking for one for 797. Wanted to look at 6-10 just drove 1000 k and wife asleep but this saw is drawing me. The DJ8J plug that’s listed for both saws just seems small for the 797.

 

[Sloa]

Good time at get to gather to all going. After cleaning 6-10 ignition system it got me motivated to clean up the points and backing plate on 797, was going to wait until I got last of parts.Can I use primer filler behind points, want to make sure no pin holes and stop corrosion creep. Seals on plate well and truly on, fairly playable . Can I reuse. Have new. Picked up bearings. Remove all grease. I’ve seen a couple methods to put on crank.

 

[Bigmac]

Good time at get to gather to all going. After cleaning 6-10 ignition system it got me motivated to clean up the points and backing plate on 797, was going to wait until I got last of parts.Can I use primer filler behind points, want to make sure no pin holes and stop corrosion creep. Seals on plate well and truly on, fairly playable . Can I reuse. Have new. Picked up bearings. Remove all grease. I’ve seen a couple methods to put on crank.

Paint is fine, there are some things you doesn’t want to paint, but they ar minimal, I would replace the bearing and seal when apart! I have reran the outer “dust” seal but not the inner. I know it contrary to many, but I will often delete the points a dust seal and pointd box cover on the 125cc saws, I have great luck with a chip. I personally feel they rpm better. Point work, and running all the oem stuff is great too! Have several great running point 125cc.