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Discussion Starter #1
Good evening everyone!
I just received a new B & S 27HP Professional series motor for my 2002 Crafrsman GT5000 and the engine mounts are not tapped. What would be the best way to handle this situation? Pre-tap them prior to install or use bolts to bolt it down?
I am open to any suggestions, I just want it solid!
 

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The stock mounting bolts are generally self tapping, i usually lube them up and run them down with a 3/8" impact wrench...you can tap them with a tap set if you prefer, its usually a cleaner cut thread, but Ive never had any issues at all cutting them with the factory bolts.
 

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The stock mounting bolts are generally self tapping, i usually lube them up and run them down with a 3/8" impact wrench...you can tap them with a tap set if you prefer, its usually a cleaner cut thread, but Ive never had any issues at all cutting them with the factory bolts.
:ditto: Same here; the stock engine mount bolts are almost always self-tapping.

Lube 'em up and stick 'em in. Like RED said, an impact wrench really helps if you are cutting new threads with just self-tapping bolts.

If you only have a manual ratchet wrench and socket available to run the bolts in, your job will be made easier if you cut new threads with a tap first. I believe you'll need a 3/8-16 tap for these holes.
 

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Discussion Starter #4
Cool! Thank you, guys.
Whenever I think of self-tapping, I think of self-tapping screws made for steel... not bolts for engines.
 

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If you've noted, the self-tapping bolts used to hold deck spindle housings in place are difficult to remove, and in most cases, impossible. That is because the threads cut are not so good and clean. They have three 'minimal thread' areas where the 'cuttings' must accumulate as they don't have grooves like a normal tap.
Try removing the engine mounting bolt you just drove into place with a rachet wrench or impact. It does not want to come out cleanly as a tapped thread would. It fights all the way.
That is great if you never plan on removing the bolt, or think it will never have to be removed. But, wait a bit, with wet grass clippings, Florida salt air, rain, and passerby dogs that have to mark... and soon you won't be able to remove the bolt.
I traded engines from one mower to another for a friend, and had no problem as they were too new to be 'married', but when I went to trade them back, two of three bolts came out in one piece, but the one under the carburetor would not budge, and I broke the head off.
I kind of think I'd like the threads to be friendly, but not THAT friendly so I can remove them without snapping something. When running bolts into the sump, I want to be sure that I do not mess the threads up as that can be a costly mistake. Seems to me it is easier to get one of the bolts 'cocked' in the un-tapped hole, and end up with a mess...
I'd sooner tap, and be done with it.
tom
 

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Discussion Starter #7
Didn't want to leave you guys hangin'...
I did, indeed, tap it...
Everything went in like butter!
I started to try using the bolts, but didn't have that piece of mind that I had using a tap.
Thank you!
 
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