[windfish]

Today I picked up a 7260, 35 bucks and it was about 15 min from where I picked up a 4x8' utility trailer so I figured why not.

Came with a leaf shredder, bag, side discharge plate, and the 1978 Lawn-Boy mechanic's handbook.

Unfortunately I had a few stops to make on the way home, so I took a cable lock and tied the mower to the trailer. Managed to thwack the carb bowl screw with the cable, so now it pukes gas. Probably time for a carb rebuild anyways... but still.

Then while I hosed the gas off the deck I found a crack -

It was dirty under the chute so it wasn't really noticeable - I doubt the PO knew about it, but you never know.
Seems a shame, as the rest of it is in decent shape. Is there a good way to stop it from spreading? JB Weld, epoxy?

 

[GTP]

Today I picked up a 7260, 35 bucks and it was about 15 min from where I picked up a 4x8' utility trailer so I figured why not.

Came with a leaf shredder, bag, side discharge plate, and the 1978 Lawn-Boy mechanic's handbook.

Unfortunately I had a few stops to make on the way home, so I took a cable lock and tied the mower to the trailer. Managed to thwack the carb bowl screw with the cable, so now it pukes gas. Probably time for a carb rebuild anyways... but still.

Then while I hosed the gas off the deck I found a crack -

It was dirty under the chute so it wasn't really noticeable - I doubt the PO knew about it, but you never know.
Seems a shame, as the rest of it is in decent shape. Is there a good way to stop it from spreading? JB Weld, epoxy?

You can drill a small hole at the end of each end of the crack and fill the entire crack and holes with JBWELD or take it to a shop for a quick weld. It doesn't look that bad.

 

[Orangedotfever]

You can drill a small hole at the end of each end of the crack and fill the entire crack and holes with JBWELD or take it to a shop for a quick weld. It doesn't look that bad.

+1. Drill the holes until you get it running and checked out. Then go get it welded up. Very nice looking mower there.

 

[windfish]

Huh. So like what SafeLite did for my windshield, only they had a vacuum to force their fixer into the crack.

Would it be a good idea to take an angle grinder with a thin cutoff blade and make the crack wider so I can get some JB Weld into it?

I thought, in general, that these aluminum decks are a pain / impossible to weld right because of their low melting point?

 

[2cycled fruitcake]

hey, way to go, that's a real good find

 

[imaLawnBoyFreak]

Nice Machine, I agree with drilling a small hole to stop that crack... It doesnt look bad, but you dont want it spreading. I think i have a spare carb for that machine...

 

[gcmartin1]

Great find. A shop can weld the deck. No worries. Just screw the ends of the crack.

 

[Orangedotfever]

Huh. So like what SafeLite did for my windshield, only they had a vacuum to force their fixer into the crack.

Would it be a good idea to take an angle grinder with a thin cutoff blade and make the crack wider so I can get some JB Weld into it?

I thought, in general, that these aluminum decks are a pain / impossible to weld right because of their low melting point?

Since that crack is right by the wheel and will take a lot of stress, I wouldn't count on JB weld to hold it. Get it welded. A good tig welder will fix that up just fine. They weld aluminum all the time. Let the welder do the grinding.

 

[rscurtis]

Could that be a magnesium deck? A little more challenging to weld than aluminum.

 

[grn68rt]

Take the model tag off and put it on another uncracked deck. Would be cheaper(?)and alot less work.

 

[LawnboyKS]

Looks like aluminium, as I don't see the "mag" on the deck, usually under where the carb is mounted to the motor. Nice looking mower! Looks like it's had very few hours put on it for it's age!

Aluminium can be welded as long as it's a good solid piece. If there's a lot of pitting underneath or if it's poor quality it may be harder though. Magnesium is nearly impossible to weld because of it's nature. There's very few people that know how or have the rod to weld it anymore, and there's always a chance of it burning up. I talked to a custom welder, happens to be a lawn customer of mine, he said he has done it but has to do it at another guys shop because he has the special fire extingusher you need on hand just in case... He also said it's usually a crap shoot if it will weld or not, often there are impuritys trapped in the casting that make for a bad weld. I had one shipped to me that arrived broken thanks to UPS. The seller had another Mag deck and shipped me a replacement...

 

[Orangedotfever]

I have two of those bull nosed decks and they are both aluminum.

 

[Lawnboy77]

Yeah, looks like that is aluminum, but you can't tell by the deck design, the deck that is pictured in my avatar is magnesium. The bull nosed decks seem to be a mix of aluminum and magnesium.

 

[bald-guy]

Yeah, looks like that is aluminum, but you can't tell by the deck design, the deck that is pictured in my avatar is magnesium. The bull nosed decks seem to be a mix of aluminum and magnesium.

I'm thinking this should be like a 7260 D with that plastic top and primer bulb.
Yes, the deck could be either material.

 

[gcmartin1]

Scrape some filings off the bottom of the deck and put a flame to it. You'll know immediately if it's magnesium or aluminum!

I'm leaning towards magnesium. The oxidation doesn't look like aluminum to me.


:fing32:

 

[Lawnboy77]

I don't see anything around or below the carb that would indicate magnesium.

 

[gcmartin1]

I don't see anything around or below the carb that would indicate magnesium.

I have two or thee decks that have no marks that denote magnesium, but the decks are indeed magnesium. That's why I've asked a few times how OMC marked the magnesium deck. Something I see is that here in southeast Texas, the aluminum decks oxidize with a white powder and the paint bubbles and flakes off in large pieces. The magnesium decks do not oxidize and the paint flakes off in very small flakes or hardly at all.

This is just my observation.

 

[GTP]

Since that crack is right by the wheel and will take a lot of stress, I wouldn't count on JB weld to hold it. Get it welded. A good tig welder will fix that up just fine. They weld aluminum all the time. Let the welder do the grinding.

+1 the drilled holes will stop from further cracking and I have had 2 decks welded (aluminum) and it took a grand total of about 15 minutes for both-if your welder guy knows his stuff. One crack was small another larger than yours and both once sanded and painted looked brand new.

 

[Lawnboy77]

I have two or thee decks that have no marks that denote magnesium, but the decks are indeed magnesium. That's why I've asked a few times how OMC marked the magnesium deck. Something I see is that here in southeast Texas, the aluminum decks oxidize with a white powder and the paint bubbles and flakes off in large pieces. The magnesium decks do not oxidize and the paint flakes off in very small flakes or hardly at all.

This is just my observation.

It was my understanding that it was mandated, due to safety reasons, that the word "magnesium" be cast into the decks, if the material was indeed magnesium. I have always heard that if it doesn't say "magnesium", then it is aluminum. You may very well be right though. It maybe that those regulations came along midway through the 70's and some of the decks were produced before the mandate became official.

 

[imaLawnBoyFreak]

That is always what i thought too, Rex. Thats why the 60s muffler plates have "magnesium" cast into them as well as the Metal Air Filters from the 60s.