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Engine basics => Engine set up tips => Topic started by: Dwayne on September 09, 2010, 08:36:12 AM
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Hi all I just scored a NIB K&B .61 baffled engine and when I tighten the prop nut the crank gets very stiff, when I loosen the prop nut the crank is still stiff and I have to tap the crank to get it to loosen up, any ideas?
Thanks
Dwayne
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Now you know why it was so cheap?
I have no experience with that particular engine, so take this all with a grain of salt -- hopefully someone who knows more will say more.
The problem is that there is insufficient clearance for the crank and prop drive. Reasons that I can think of for this happening are because:
- It's a lemon, and has been wrong from day 1
- someone changed bearings and put them in wrong
- someone put in the wrong bearings
- someone put them in with crud in the hole which prevents them from seating all the way in
- the case is damaged, and it either prevents the bearings from seating or raised a bung or burr in the nose by the prop drive
- the prop drive or crank is damaged, allowing the prop drive to go on the crank too far
- someone assembled it with an incorrect shim between prop drive and crank case
- ??
-
Now you know why it was so cheap?
I have no experience with that particular engine, so take this all with a grain of salt -- hopefully someone who knows more will say more.
The problem is that there is insufficient clearance for the crank and prop drive. Reasons that I can think of for this happening are because:
- It's a lemon, and has been wrong from day 1
- someone changed bearings and put them in wrong
- someone put in the wrong bearings
- someone put them in with crud in the hole which prevents them from seating all the way in
- the case is damaged, and it either prevents the bearings from seating or raised a bung or burr in the nose by the prop drive
- the prop drive or crank is damaged, allowing the prop drive to go on the crank too far
- someone assembled it with an incorrect shim between prop drive and crank case
- ??
Thanks Tim that's about what I was thinking, I ony paid 60 bucks including shipping but I sure hope it's not a lemon.
Thanks
-
Now you know why it was so cheap?
I have no experience with that particular engine, so take this all with a grain of salt -- hopefully someone who knows more will say more.
The problem is that there is insufficient clearance for the crank and prop drive. Reasons that I can think of for this happening are because:
- It's a lemon, and has been wrong from day 1
- someone changed bearings and put them in wrong
- someone put in the wrong bearings
- someone put them in with crud in the hole which prevents them from seating all the way in
- the case is damaged, and it either prevents the bearings from seating or raised a bung or burr in the nose by the prop drive
- the prop drive or crank is damaged, allowing the prop drive to go on the crank too far
- someone assembled it with an incorrect shim between prop drive and crank case
- ??
Thanks Tim that's about what I was thinking, I ony paid 60 bucks including shipping but I sure hope it's not a lemon.
Thanks
Most of the things with a bearing can be checked quite easily
The K&B 61 does not use a shim between the collet and bearing.
I've come accross a few with the wrong collet which has a sharper taper and does let the thrust bearing go back too far and rub the case.
You also mention that you hit the crank to release the thrust washer. Not a good idea as you may have driven the crank back slightly , and that would be enough to cause your problem.
It should only be removed with a puller, even a cheap battery terminal puller can be used. Just use something to protect the tip of the shaft
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Sounds like the brgs. aren't fully seated in their pockets.
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Thanks for the replies, I pulled the crank filed the front of the case gave it a thorough cleaning and tapped the rear bearing down on the crank using a piece of brass tubing, put it back together making sure the bearings are fully seated and it is much better now so I think the rear bearing wasn't seated all the way, anyway this is the first time I've done this so I'm quite proud of myself y1 <= #^ ~>.
Thanks again guys
Dwayne
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Congrats to you on joining the "fraternity of bearing seaters". Seriously engine work can be a lot of fun. Just remember that if it seems like as bad idea, it usually is.....
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Hopefully the bearing race didn't get "brinelled" when you initially tightened the prop.