Loss of drive unit

[wtwmoney]

I have a '84 Carrera with twin 454's. Today while I was on the lake I went from half throttle to full throttle rather quickly. And one of the drive units quit working all together. I literally lost everything; no forward or reverse. Earlier on of the units seemed like it was trying to neutral. Could this be a coupler or something else. The drive units are I believe '83 or '84 pre-Alphas. I'm not for sure. I do know they have an eyelet on top of the upper unit. Any help will be greatly appreciated. Thanks

 

[Reel Poor]

Re: Loss of drive unit

It could be a coupler, prop hub bushing or the drive itself. I would check the prop first by scribing a line on the hub and the prop. Run the boat again then look to see if your scribed lines are still indexed in a straight line.

 

[Haut Medoc]

Re: Loss of drive unit

Welcome to iboats....
You sure those are alphas?
Its uncommon to have Alpha drives behind 454's.....
Mainly because they are only rated to 300 HP......
Did the engine overheat or did you smell burning rubber?
That would be a sure sign of a bad coupler......
Can you post up your engine serial #'s so we can know for sure what you have?.......

 

[Bondo]

Re: Loss of drive unit

I have a '84 Carrera with twin 454's. The drive units are I believe '83 or '84 pre-Alphas. I'm not for sure. I do know they have an eyelet on top of the upper unit.

RP,+ Haut are headed in the right direction, to find out What broke,.......

I'm just Amazed at the Driveline you have.......

I've Never heard of a BBC, in front of a Pre-Alpha before......

 

[wtwmoney]

Re: Loss of drive unit

I'm not for sure exactly what drives I do have. Is there an easy & quick way to find out? The engine was actually running a little cooler than the other one. I never smelt a burning rubber smell. I'll try to get you the serial no. of the motors. There's no way I can get any # of the units. I'm working on getting the boat back in condition. The hull is rather in great shape. Just everything else is rather been jerry rigged. That's why I'm having trouble telling what I actually have. I do know the motors are Gen. 4 454's.

 

[Don S]

Re: Loss of drive unit

Mercruiser did use the 454's with the Alpha drives for a few years............ before they invented the Bravo drive.
That's how they found out the Alpha's were only good for 300 hp max.

Look on the starboard side of the engines for a Merc serial number. That will help in IDing the engines and drives.

 

[wtwmoney]

Re: Loss of drive unit

I'm so sorry I guess I didn't mention that they were Chevrolet engines and not Mercruiser. Didn't know if it made a difference or not.:devil:

 

[Haut Medoc]

Re: Loss of drive unit

They are GM engines.....
Can you see the ID tags or not?
If not, can you post a pic of the drive?
If it didn't overheat, I doubt it is the coupler.....
If you have absouloutly no movement, while in gear, I doubt that it is the prop, but that is easy enough to check......
That leaves the drive or the drive cable as the culprit....
Visually inspect the shift assembly for any obvious signs of faulty performance......
If it all looks good, you will need to pull the drive & test further.......:'(

 

[Bondo]

Re: Loss of drive unit

I do know they have an eyelet on top of the upper unit.

That tells Me they're the old Mod. 1s, or Pre-Alphas.....

If I remember Right,....
Up at the Top of the vertical Shaft, there's an O-ring Groove that tends to Snap the Shaft Off Clean when Hammered alittle Too Hard.......

 

[wtwmoney]

Re: Loss of drive unit

If I remember Right,....
Up at the Top of the vertical Shaft, there's an O-ring Groove that tends to Snap the Shaft Off Clean when Hammered alittle Too Hard.......[/quote]

Does that mean that I can pull the top off of the upper unit & visually inspect the shaft? Or further disassemble the unit? Also, I removed the prop today and everything appeared to be intact the way it is supposed to be. There is no tags any where; on the top of the trans. is a spot that has rivets in but the tag has been removed. Is there any other way of telling? One problem is the previous owner painted the drive units with a brush and black paint.