Super Jet Engine coupler sitting higher than driveshaft coupler??

[93rx7]

So I've been piecing together this RN hull and running into a few issues.

Finally got the pump aligned and the driveshaft centered in the hole. Took 4mm of shims at the back to do this.

After that, got my motor mounts in and dropped my engine in. With NO shims under the engine the engine's coupler is about 2mm higher than the mid shaft coupler at the top and port side of the hull. On the starboard side it seems like the opposite is true, the pump is higher than the engine. Anybody have a clue what is going on? I've never had this much trouble getting a drive train aligned.

 

[swapmeet]

4mm of shims on a pump sounds like way too much to me. I guess its possible that something is wonky on yours but that doesn't sound right.


What motor mounts are you using? Perhaps they are couch mounts?

Is the midshaft bolted in?

 

[93rx7]

The pump is out of a wave raider I believe.. it's goofy for sure. Has trim and stuff. But the driveshaft is dead nuts centered in the mid shaft hole now.

I believe they are in fact couch mounts. And yes midshaft is bolted in. I've never had to shim a midshaft and my hull has 0's on it but the midshaft I have is not the one that came in the ski.

 

[chadetroit]

As swap was referring to up above, I ran into the same problem a few weeks ago. Couch mounts are about 1/8 of an inch taller than the standard RN mounts

 

[IS0LD0UT]

Couch mounts are higher. I have had luck with my RN, by loosing the hull side bolts and pushing the mounts as far as they can go twords the outside away from the motor. Or you can have them cut down.

 

[93rx7]

Ahhh that would make sense.

I'll try moving the mounts outwards and see if that's enough. Also I have less than 2mm clearance between the two couplers when the motor is pushed all the way back. I set the midshaft at 19.5mm. Is it OK to just slide the motor forward to get my 2-4mm clearance or is that incorrect?

 

[IS0LD0UT]

IMO a couple of mm forward for the engine is fine. There is lots of room for movement there.

 

[93rx7]

Allright.. then I'm ok with that. Is there a DIY way of shaving the mounts down if I have to go that route? Belt sander and light pressure?

 

[chadetroit]

You would have to use a real heavy grit or you will be there all day, but with patience it could be done. Should be milled or get standard mounts

 

[JetManiac]

Easier to hog out the holes toward the inside of the holes to allow mount to slide farther outward.

 

[swapmeet]

Yeah I wouldn't shave them too much, thats where most of your strength comes from. Although if I were to do it with the tools I have, i'd use a grinder with a flap wheel to do heavy cutting and then smooth it out on a belt sander.

 

[IS0LD0UT]

Did that work for you?

Sent from my KFTT using Tapatalk HD

 

[BombThreat]

I tried using raider mounts and it was a good 1/4" too high from the mid shaft coupler. Got some sj mounts and I didn't need any shimming at all...then I let a buddy try the couch mounts in his sn and they fit perfect without needing any shims

 

[djraider700]

Just put in couch mounts on my SJ and actually had to add a thin shim to one of the rear mounts. Thanks Jetmaniac!