No gears in the middle of the sea!-gctid386101

[Guest]

Hi All,

Having a few problems with my boat. It's a mash of a Volvo AQ211a V8 block married to the original Merc V8 ancillaries (manifold, risers, ignition, leg, transom shield etc). Both blocks were GM blocks anyway ÔÇô (only difficulty I've found so far is that the exhaust risers have to come off to get a socket onto two of the plugs but that doesn't worry me to much).

Out last weekend, cruised at 30kts for 15 mins, came to leave and knocked her into astern. When I came to move the stick forward into ahead I got the revs but continued to move astern (just faster). She appeared to be stuck in astern. I killed the engine and had a look. All seemed ok so started her up and this time I couldn't select any gears.

A few weeks previous to the trip my marine mechanic had re-adjusted the gear linkages after removing the leg to service it. We had been out once since with no problems although that trip was only short.

My mechanic seems to think (which I find odd) that the marriage of the AQ211a might not be working. I have spoken to a Merc trained mechanic who has said that the Alpha 1 leg can handle up to 300hp and is widely accepted as one of the most reliable legs ever made. My leg is geared correctly for the higher output of the AQ211A (as confirmed by my own mechanic previously). The linkages for the leg are still Merc linkages that are bolted to the exhaust riser (as it's also a Merc riser). So in terms of linkages sending messages to the leg, it's all Merc as it was previously.

I can't understand why my mechanic thinks it could be a problem with the marriage of a VP to a Merc leg when all the controls for the gears are original Merc and all the block does is provide the suck, squeeze, bang, blow when required. Do you think he might be covering his behind or might he have something?

NOTE: (Temps are always spot on, ignition is Merc Thunderbolt and always starts on the button.)

Anyone got any ideas or suggestions?

[2850Bounty]

Let's see if I'm understanding you:

Engines are GM SBC's.... and were originally in a Volvo Penta application, correct?

They are now mated to a pair of Merc A drives, correct?

Along with the transition, all Merc components were used, I mean ALL MERC Components......., correct?

There is Nothing, Nada, Zip Merc "A" drive re; shift linkage, shift cable, Shift Interrupt, Gimbal Housing, transom unit, etc., that even remotely ressembles the Volvo Penta drive system.

The only thing Volvo Penta would have been the engines only.

This mechanic is somehow trying to relate the previous Volvo Penta application to the NOW Mercruiser "A" drive shift issue, correct??????

If there's even a remote chance of the answer being YES, I'd say find a new mechanic.

.

[Guest]

The boat is an Arriva 2050. The original application was a Merc 5.0 V8.

ONLY the engine and carb has been swapped out for a Volvo 5.0 V8. Everything else you mention has remained Merc (even the risers, transom sheild, ignition system, even the cooling side of things appears to be Merc). The only thing to have changed (I believe) is the engine coupling to enable the VP engine to Merc leg mating (and I know that works as it has never caused a problem previously).

This is what I cant understand - all the cable set ups to the leg (both Merc) are original Merc. Even the ignition kill switch is there and working perfectly as it would on a Merc engine (being mounted to the side of a Merc riser). So I would assume even though the heart of the beast is different, it is still essentially doing the same thing (beating). It gets told to beat faster by the throttle cable and as the gear linkage is Merc (as is the leg), the signals sent to the leg by the linkage would be the same no matter what dam engine was in the middle (as it is its all Merc as it was originally anyway).

So does anyone see any potential issues with the engine being a VP and everything else being Merc or is it just my mechanic?

[Guest]

Cue_Ball wrote:
The boat is an Arriva 2050. The original application was a Merc 5.0 V8.

ONLY the engine and carb has been swapped out for a Volvo 5.0 V8. Everything else you mention has remained Merc (even the risers, transom sheild, ignition system, even the cooling side of things appears to be Merc). The only thing to have changed (I believe) is the engine coupling to enable the VP engine to Merc leg mating (and I know that works as it has never caused a problem previously).

This is what I cant understand - all the cable set ups to the leg (both Merc) are original Merc. Even the ignition kill switch is there and working perfectly as it would on a Merc engine (being mounted to the side of a Merc riser). So I would assume even though the heart of the beast is different, it is still essentially doing the same thing (beating). It gets told to beat faster by the throttle cable and as the gear linkage is Merc (as is the leg), the signals sent to the leg by the linkage would be the same no matter what dam engine was in the middle (as it is its all Merc as it was originally anyway).

So does anyone see any potential issues with the engine being a VP and everything else being Merc or is it just my mechanic?

No issues as long as the proper parts were swapped out, and it wouldn't really go together without them being swapped out.

I have spoken to a Merc trained mechanic who has said that the Alpha 1 leg can handle up to 300hp and is widely accepted as one of the most reliable legs ever made.

That's a bit of a stretch from a Merc mechanic, the Alpha is the lightest-duty and cheapest drive and is usually considered a throw-away... they're good drives for the money, but nowhere near "one of the most reliable legs ever made".

Sounds to me like something in the "re-adjustment" has caused the issue - perhaps something is not tight, or it is not set up/reinstalled properly.

[2850Bounty]

Cue_Ball wrote:


So does anyone see any potential issues with the engine being a VP and everything else being Merc or is it just my mechanic?

See post #2 again. It is clearly this person disguising himself as a Marine mechanic!

[Guest]

A few weeks previous to the trip my marine mechanic had re-adjusted the gear linkages after removing the leg to service it. We had been out once since with no problems although that trip was only short.

I think we have the answer!op-

[Guest]

Ok - the mechanic has just looked at the boat and we seem to have sourced the problem.

It was nothing to do with the gear linkage adjustment. Where the Merc Alpha One (Gen 1) leg meets the gimbal housing, the gear linkage to the leg is controlled by an arm that pops up out of the lower unit. This arm has a forward facing lug on it that locates with an upside down "U" shaped piece on the gimbal housing (moving in and out of gear moves this "U" shaped piece left or right which in turn moves the lug and shaft running down into the gear box.

For some reason the lug at the top of the leg's shaft had dropped down below (and therfore out of) the range of the Gimbal housings gear linkages (as in it has dropped down further into the lower unit), therfore moving in and out of gear was moving the parts it was meant to but this wasn't being transferred to the gear box.

I watched the mechanic remove the leg and he has now gone away to source an exploded diagram of the area concerned. I looked at the leg myself and have noted that there is play in this shaft that runs down into the gear box, I can pull it up and push it down into the gearbox with a total travel of around 1.5cm's. I have checked that it still engages both gears throughout the entire travel range (and its does).

What concerns me is that something with such precise adjustments (being only a few mm between ahead and neutral and a few more between neutral and astern) can have such a large amount of play in an up and down movement.

Previously the mechanic did split the leg to inspect internals. My thinking is that this arm with lug on top should have some form of spacer within the unit that holds this arm at its highest point stoping it from falling out of the range of the gimbal housing linkages.

Is anyone familiar with the Alpha One Gen 1 that could give a reason as to why this might have happened or why this could happen so that I can check tolerances before the mechanic puts the leg back on?

Thanks to all that have helped so far!

[dktool]

If there's even a remote chance of the answer being YES, I'd say find a new mechanic.

Yea, time to go shop for a REAL mechanic !

A few weeks previous to the trip my marine mechanic had re-adjusted the gear linkages after removing the leg to service it. We had been out once since with no problems although that trip was only short.

I think we have the answer!

+1

There is a cir-clip or e-ring on the vertical shift shaft in the lower unit that maintains it's position.

If the "mechanic" removed only the lower unit previously, my guess is that when he reinstalled it, the male / female shift coupling (upside down "U" shaped piece) was not line up and he forced the lower into place and in the process broke or dislodged the clip on the shift shaft.

That would explain the shift shaft dropping into the lower unit farther than normal.

My 2 cents

[Guest]

Is this Circlip within the gear box? I can't see signs of a circlip on the outside of the unit (holding the shaft up).

At present there is about 1.5cm's play in the up/down movement of the intermediate shaft on the leg. Which due to gravity obviously always wants to fall to its lowest position.

[dktool]

Is this Circlip within the gear box?

Yes, # 30 in this drawing. It is located near the bottom of the shaft, (drawing is miss leading) just above the splines that engage in the shift spool bell crank.

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