Thanks to everyone who has helped out so far. Here is where the problem stands now:
Yesterday I tried to take apart the coupling between the transmission
and the drive, however I found out that in order to get it apart that you need to remove the outdrive from the boat. (Why it is designed this way is beyond me!). Since I wasn't able to remove the coupling I put it back together and in doing so noticed that one of the bolts "may" have been loose.
Since I had taken things apart and put back together we ran the engine while at our mooring
, in doing so we saw no shakes in either reverse or forward, so I thought I had fixed it. Today we took the boat out and ran up and down the ICW
and found the problem was better, but not fixed. Now the vibrations start at 2800 RPM and are still there at 30000 while in forward (we didn't dare go any higher due to the sever shaking). In reverse things are better than they ever have been - no shakes seen right up to 3300 RPM. So I seem to have removed the vibrations at the lower RPMs, but not the higher RPMs, which incidentally are the RPM we normally run at!
Over several trials of moving the RPM from idle to max, once it did not vibrate at all (fluke?), ever other time it did except when manual pressure was applied to the shift lever on the transmission
(right at the transmission) pressing it "farther" into forward (it didn't move, just pressure). When the pressure was applied at the beginning of the trial all the way up to 3000 rpm the vibration did not occur - this was consistent every time we tried it. If pressure was applied to the shift lever once the shacking started it had no effect.
When the engine is shaking, looking at the coupling (see photos below) between the transmission an the outdirve the major movement is on the transmission/engine side.
When the engine is shaking looking at the outdrive it is moving but only slightly (looks like the shake comes from the engine, but I can't be sure)
Of the suggestions see in previous posts:
- I have ruled out a bad Injector, as nothing is seen with transmission in neutral while running engine from Idle upto 3000 RPM.
- Have not been unable to check the bolt that Bradley mentioned. (Need to haul boat out)
- Have not been able to disconnect the transmission from the drive, to isolate transmission from drive (Need to haul boat out)
- Transmission cone has been ruled out as nothing seen at Low RPM and I don't think things are slipping.
Pat - I think we have done what you mentioned - What are your thoughts ?
you could also have a problem with the dampner plate. But those are rare.
Are you comfortable shifting the trans at the trans? if so disconnect the cable and shift it firmly holding pressure while someone brings up the RPM. See what that does.<quote>
I planning on taking a closer look at the coupling between the transmission and outdrive to see if it looks out of alignment, as something did change there.
I really don't want to haul the boat until I'm pretty confident as to where the problem is - Any other suggestions Ideas ?
Thanks again for all the help.
Note: this is not bolted back together in this picture