7900 OOPS!

[VINIFIREWOOD]

Yup I'm wearing the dunce hat tonight. Skid steer vs 7900 and guess who won. Ya not my saw.
So question for you fellers that have been inside and out with these things. By looking at the pics below is this thing fixable or should I just count my losses.
What I do know I would need for parts; flywheel/recoil cover and black shroud behind it, top cover(not filter cover), top handle.


The boss for the cover and break handle is broke off. Can this be built up with weld and drilled and tapped?



Crack in the clutch side case by my thumb. Obviously if the saw were torn down can this be welded?

 

[WoodChuck'r]

What fuel ratio you running...??

Wouldn't have happened if ya were running 32:1.

 

[VINIFIREWOOD]

What fuel ratio you running...??

Wouldn't have happened if ya were running 32:1.

300:1

 

[Jacob J.]

The case can be welded, but you'd have to tear it down to the case halves likely.

 

[VINIFIREWOOD]

The case can be welded, but you'd have to tear it down to the case halves likely.

Thank you for that.

Finally heard back from a machinist/ welder buddy of mine says yup no problem.

 

[dall]

sorry about your loss but if can get it repaired do it or see if can find new case the pics of your saw is usually how I like to get them so if can get fixed do it and sorry again

 

[nmurph]

Thank you for that.

Finally heard back from a machinist/ welder buddy of mine says yup no problem.

You need to make sure he has the correct rods. Does he understand this is Mg?

 

[DanTheCanadian]

Rods? You mean tig wires right?

 

[dall]

he means welding rods if not the same metallurgically the weld will not hold either the case will break again right at the weld or the welding rods will just melt the base metal and be harder to fix

 

[VINIFIREWOOD]

You need to make sure he has the correct rods. Does he understand this is Mg?

Ya he knows and has the correct rod.

 

[fordf150]

Looks like a good excuse to rebuild it. New case halves are reasonably priced and come with bearings installed if repairing it doesn't work out. Brush hogs and chain saws don't end well either. Had a couple of those come in last fall

 

[Jacob J.]

That's why a lot of welders/machinists don't want to do Mag, because there's a lot of alloys in use and sometimes it's hard to tell what alloy it is.

 

[VINIFIREWOOD]

Fortunately even if welding it doesn't work out, given he is a lifelong friend, it won't cost more than a case of his favorite brew.

 

[fearofpavement]

I think I would replace the saw with a runner and be on the lookout for a blown up 7900/6400 that you can take the two of them and make a good saw. Eventually one will come to market and that would be the best solution in my opinion.

Note: I would recommend not buying any parts until you get this thing completely torn down and assessed. You may find other damage.

 

[VINIFIREWOOD]

I think I would replace the saw with a runner and be on the lookout for a blown up 7900/6400 that you can take the two of them and make a good saw. Eventually one will come to market and that would be the best solution in my opinion.

Note: I would recommend not buying any parts until you get this thing completely torn down and assessed. You may find other damage.

I will have to get another saw while this one is down. This saw doesn't really see a lot of run time during my busy season. Maybe 5 cuts on the average job. For that reason I never got a backup for it. Now that firewood is in such high demand around here I need it.
I will be tearing it down further before ordering parts or doing any welding. I did spin the flywheel and everything seems ok there.

 

[WheresWally]

If he is good, it will be easy for him, i work with a couple of welders that do this stuff all the time, trouble is, identifying the composition and buying the correct filler can cost more than a case of his beer of choice, in some cases, the filler can be more expensive than the part you are trying to weld.

 

[makguy]

If you don't have a preference on color, find a Makita equivalent that has been straight gassed (I've had good luck with my local HD tool rentals) and salvage the crankcase off of it.
Otherwise you're looking at buying new, or trusting the welds to hold up.