Engine alignment - front motor mounts are nearly bottomed out

[aviationMx]

01 216 chap/ 5,0 305 efi/ OM049123/alpha gen 2

Have had the boat for 4 years and had some issues with shifting so I pulled the drive to replace the lower control shift cable and bellows. When checking the engine alignment, I had only spline grease marks on the top of the tool, lowered the front motor mounts and now have 360 spline marks but only 2 threads left on the front MMs. I would guess I dropped the front about 1/4 ".

Additional info- in the paperwork for the boat is a brochure for a reman engine- not sure when this was done or why someone would replace a 305 with a 305. I'm not sure how to research engine to confirm replacement except that is has 300 hours on a 17 year old boat ( which may mean nothing). The U joints are the sealed type and appear to be in good shape although it appears I was running an out of aligned coupler for a season.

1- The rear mounts are very clean with no rust although I see one fiber washer on the port side
2- Can I run the boat for a season with only 2 threads left on the fwd MMs adjustment and tackle the rear MMs later?
3- The gimbal bearing is well greased and is rotates smoothly, although it doesn't "swivel" - my alignment tool unscrews and I can place it in the bearing only- it doesn't move at all- locked in a single axis.
4- if I need to upgrade the rear MMs to ( i think) SB 2003-11 for 0M660000 and older, can just replace the washers or do I need to press out the rubber mounts ( I don't have the ability to pull the engine) or is there another option to raise the back of the motor?

thank you in advance, this is my first choice in forums to find info. I do have pics of the rear MMs if I can figure out how to post them.

Chris at SML in VA

 

[GA_Boater]

Hi Chris.

Can't help much with your questions, but a gimbal bearing should rock in the tolerance ring. It isn't a loose fit, the bearing to ring fit is pretty snug.

On adding pics - Click on Forum Help in the sig below and take a look at the tutorial about attaching pics.

 

[aviationMx]

Thanks GA,

 

[aviationMx]

[No message]

 

[wellcraft-classic210]

1 suggestion--

try using a 1.o diameter shaft by about 8 inches long inserted into the engine coupler which should fit well -- rotate the engine to see if it stays on center in the larger gimbal bearing opening to see if their is any runout in the coupler.

Split the difference if its not excessive & see if you mounts are back in the normal range .

 

[aviationMx]

Good point, I haven't rotated the engine yet.

 

[kenny nunez]

The bottom line is the engine needs to come out and the mounts replaced in the mount housing.
If you can get alignment with the adjusting nuts bottomed out that should work.
There is one more thing that will be a “Band Aid” temporary fix. Remove the top nuts and raise the engine high enough to remove the bottom nuts. If you do not have a lift use a small bottle jack. Get some 3/4” I.d. Flat washers and cut a slot so the washers will slide over the mount studs. Lower the engine to get the alignment then use the washers as a shim. Then tighten the mount nut and wrap tape around the shim washers to keep them in place. Keep a eye on the nuts that they stay tight.

 

[aviationMx]

Chose to remove the gimbal bearing...prob 17 years old. Due to misalignment, it wasn't flush and I had to chain drill the race..but it's out and the everything looks good. took 6 hours, what a PITA. hopefully the new bearing ( current sitting next the jagermiester in the freezer) will sit properly and help the engine realignment.

 

[aviationMx]

Installed new gimbal with no change on the alignment issue, the port rear motor mount fiber washer spins the starboard fiber washer looks crushed or at least doesn't turn. would that throw off the alignment to point that no forward MM adjustment would work?

the best spline pattern I can get is 1.5 inches on top and 0.5 inches on the bottom of the alignment tool...

 

[scoflaw]

Sounds like your front mounts are uneven, putting all the weight on only 1 of the rear mounts.

 

[aviationMx]

I just checked the Fwd MMs and they're equal. Thanks for the suggestion.

 

[wellcraft-classic210]

Try the 1.oo shaft I had suggested earlier -- its much easier to rough things in than reading grease // Personally I have had better result with that and don't like the grease reading method. And dont forget to split the difference on any runout.

Try McMaster-vcarr or your local metal supplier for a short piece of 1 inch stock // Tell them what its for so you get someting close to the target od that will work. Should be the same as you alognment bar +/- .005 in or so.

 

[scoflaw]

I just checked the Fwd MMs and they're equal. Thanks for the suggestion.

Equal may not be the correct setting.

Elevate your engine at a front central point. Torque the 2 rear mounts. Lower the front slowly as you check the alignment
When you get your alignment right, then bring tension on the front mounts. 1 of your front mounts may be installed at a diff. height than the other..

 

[aviationMx]

ok, I'll give it a try, do the rear mounts take a light torque like 35 inch Lbs?

 

[scoflaw]

More like 25 ft. lbs. but look it up

 

[scoflaw]

That could be part of your problem as well. The correct torque makes an alignment difference for sure

 

[aviationMx]

Yeah, I meant ft lbs. I havent check the rear MM bolts, I assumed they were more like pins and didn't change the telemetry.
it's a good idea- I really appreciate it.

 

[aviationMx]

Just wanted to close this thread. it appears that the rear eng mounts are failing. I took some good advice and took the weight the front of the engine and retorqued the rear MM and managed to get the alignment to fall in with 2-3 threads left on the front MM. The drive is in...

thanks for the advice and I hope to get through this season before I have a pro pull the engine