I have a .61 that I need an engine mount for. I stopped in to my LHS to get one, but the mounting holes on the one I got do not match the ones on my LT-40. I do have the old mounts that my .46 was on, but I would have to drill new holes to mount the .61. Can I do this or will it weaken the mounts too much? Just in case your thinking a .61 is too much power for an LT-40, my LT-40 weighs 9.5 lbs with floats attached.

Thanks,

LT-40

I'd personally buy a new engine mount, they arent that pricey and then youll rest assured knowing that it will work and not cause you any troubles.

david

I reuse engine mounts. However a .61 will not usually fit in a .40 mount. The .61 engine is usually too wide for the mount.

Bill

I reuse engine mounts only if I don't have to drill new screw holes.

Dr.1

You really should use a new mount if you can. Drilling new holes does weaken the mount some. Now with that said, I have reused a mount before. Here's what I did. Before you drill new holes in the mount for the new engine fill in the old holes. I screwed bolts into the old holes and then cut them off flush with the mount. This will help strengthen the mount some, but it's still going to be weaker than a new mount will be.

If you do reuse the mount please consider it temporary until you can get a new mount. Trust me, having a motor mount break in the air isn't good at all.

Hope this helps

Ken

To answer the second part of your question, a .61 size engine on an LT-40 is too big. There is an old saying, "You can't make a racehorse out of a mule". The LT-40 is a basic beginner's trainer and isn't meant to do anything other than basic in flight maneuvers. However, it is your airplane and your motor and you can do anything you want with it. I personally would save up and buy an airplane better suited to the .61 engine. A SIG 4 star comes to mind.

Regards,
doubledee

Disregard everything I wrote in the previous post. Missed the part about floats (just got out of bed and obviously not awake yet). A .61 will work fine. Sorry about that.

Regards,
doubledee

Beef up that firewall a bit to hold the extra stress/

Thanks guys, I'll order a new pair of mounts from Sig. Sig usually ships really fast. I guess that would be really bad if the engine mount broke in flight. First of all you would have no power and your engine would fall to the ground. Second your plane would then become hoplessly tail heavy and you would have no chance of gliding it in.

Trust me, it's nowhere near that graceful. You still have your fuel tubing and throttle linkage holding the engine to the plane. It hangs there and becomes an uncontrollable mess. Yes, experience talking here. Take my word for it, it's an ugly site!!!

Ken

I concur with Bill..in fact...I tried it myself
Tried to put my O.S. 61 in the same mount I use to have an O.S. 46 in ....does not work, unless I start shaving off the side of the mount...which cause weakness! so...get a new one!!They are anywhere between $4.97 - $25 for an aluminum DuBro one...take your pick!!