No reverse on A4

[alcodiesel]

Hello there! I have a 1976 Atomic 4 in an Ericson 27.

After a 2 hour motor in pretty heavy seas the reverse was gone. Nothing. Forward is fine.

Thinking the reverse just needed adjusting I opened up the gear box. The reverse adjusting screw was loose and there was no lock spring.

I tightened the reverse gear adjusting nut many turns till lots of resistance was felt. No joy.

I disengaged the shift cable and moved the arm all the back, no joy.

I'm glad it's not the forward that's having the problem. I can push the boat out of the slip and sail!

Your observations, comments, questions to help me solve this are greatly appreciated.

Bill McLean
1976 Ericson 27
No Name Yet
Norfolk VA

[Al Schober]

Bill,
Fig 7 on pg 6-4 of the MMI Manual shows the transmission with the cover open. The actuating rod for reverse is up fwd near the engine, and goes side to side. There's a large hex on the manifold end. There's an actuating bar attached to the shift lever which gets pulled aft to engage reverse. The actuating bar rides on a roller in the end of the rod near the water pump. This pulls on the rod and tightens the band around the planetary, engaging reverse.
Most likely culprit here is that the roller is missing due to it's pin shearing. If you can recover the roller from the bottom of the transmission (magnet on a stick, piece of coat hanger for a rake) you can reinstall it using a #10 hardened bolt.
There are other possibilities. Can you take a picture?

[CalebD]

Prop condition

Have you checked for any growth on your prop?

I know I have some barnacles on my prop and it has only gotten worse as the season has progressed. Today I felt very anemic reverse but still had some forward thrust from my 2 blade prop.

[alcodiesel]

Bill,
Fig 7 on pg 6-4 of the MMI Manual shows the transmission with the cover open. The actuating rod for reverse is up fwd near the engine, and goes side to side. There's a large hex on the manifold end. There's an actuating bar attached to the shift lever which gets pulled aft to engage reverse. The actuating bar rides on a roller in the end of the rod near the water pump. This pulls on the rod and tightens the band around the planetary, engaging reverse.
Most likely culprit here is that the roller is missing due to it's pin shearing. If you can recover the roller from the bottom of the transmission (magnet on a stick, piece of coat hanger for a rake) you can reinstall it using a #10 hardened bolt.
There are other possibilities. Can you take a picture?

Dang, I guess I am becoming an A4 nerd already. I could picture everything you described so well. I will do some magnet fishing and try for a picture but I do not think I have any camera that will focus that close. Is this roller viewable from a pic of a working transmission? I can always compare the two. Thank you!

[alcodiesel]

Have you checked for any growth on your prop?

I know I have some barnacles on my prop and it has only gotten worse as the season has progressed. Today I felt very anemic reverse but still had some forward thrust from my 2 blade prop.

Good idea but the prop is not turning at all in reverse. And yes the prop was covered with barnacles but they were all displaced when I hauled the boat last week. Thanks.

[Al Schober]

The end of the actuating rod towards the water pump has a slot in it. Either the roller is in the slot or it isn't.

[alcodiesel]

Thank you. I ordered the manual you wrote about. I'll get back into the tranny later today and look for that roller. And take a pic, I discovered my bronze age phone takes pretty close pics.

[Al Schober]

Oh good, another MMI Manual sale! Good reading...
Hey Bill, if your magnet picks up any other parts, save them and take a photo. We might be able to tell you where to put them - errrr... I mean, where they belong. You might find a short dowel pin, or even the actuating bar! But don't try to probe any further than the fwd end of the gear case - there's a web across the oil pan there that tends to hold gear parts in the reversing gear. There is a drain hole in the web, but only small stuff fits through - and is gone.

[alcodiesel]

I cannot find the roller you describe in figure 3 ,pp 6-4 of the manual that came today.
I magnet fished for anything in the bottom of the trans case and came up empty handed.
Attached is a pic of the area I think you are writing about. Maybe I am looking right at the answer but can't see it.

Is the pin IN the forked part on the water pump side of this rod? I did not check in that fork part. DOH! I think I see how this thing works.

Thank you.

[Al Schober]

Bill,
Here's a photo from the engine in my garage. I've taken a shot of the reverse mechanism, and labeled the actuating bar and the roller. In the photo, the actuating bar is pulled all the way aft so reverse gear is engaged. If yours looks different, let us know how.

[alcodiesel]

Thanks Al. Your picture shows it all. I'll look, or at least feel around, for the roller in the fork. Should I hope it is gone? (meaning an easy fix.)

[Al Schober]

Bill,
If the roller is missing from the slide bar, you should go pearl diving again - should be in the bottom of the case. Paragon parts are hard to find: the assembly with roller is OXK-A87, roller is OXK-88, and the pin is OXK-97 - if you can find them . And removing/installing the slide bar isn't easy - requires a) opening the gear case, or b) making a hole in the manifold side of the gear case. This hole in the gear case is called the 'Kaminsky' modification - a hole tapped 3/4" NPT with a plug. I had this done to the garage engine while I had things at the machine shop.

[alcodiesel]

A4 reverse is back!

Al, thanks for the picture and indicating it is in reverse. It's been a steep learning curve .
Nothing looked broken or missing when I cycled fwd to reverse.

My first guess turned to be correct. On the long motor run the adjusting nut simply loosened. I adjusted it so I could turn the shaft in neutral and can't turn the shaft in reverse. It works fine under power. DOH!

There is no clip to hold the nut from loosening.

Any ideas to prevent it loosening again? I am guessing wiring it somehow.

[edwardc]

There is supposed to be a "W" shaped locking spring clip that holds the nut by two opposing faces. It expands to allow the nut to be turned 1/6 of a turn at a time.

See #24 in this diagram. You can also see part of it in Al's post #10 in this thread.

[Al Schober]

Bill,
That spring clip isn't in the Moyer online catalog. I recommend you give a call to 610-421-4436 and see if they have one they can send you.
I see from your photos that yours seems to have had the two sides break off - the bolt and the rest of it still seem to be in place.
The part is available from Great Lakes Power Products - Paragon p/n 1XE-331A. $4.84 plus shipping. Call Charlie Rother at 440-951-5111 x293.