Ratcheting Into Reverse - Mercruiser Alpha One Gen 2

[taterchip22]

Recently bought a 2005 Chaparral 204SSI which has the fuel-injected 5.0 and Mercruiser A1G2. The prop installed on the boat was a chipped up aftermarket 4-blade with aftermarket pitch. From the marina parts dept. (Main Channel Marina, Syracuse, IN) I had the correct prop ordered and installed it.

When I bought the boat, it had zero shifting issues into forward or reverse - even if I shifted slower than recommended. I had it out 3 or 4 times before changing the prop. I changed the prop myself, careful to follow the instructions to the letter. Following the change, I now have ratcheting and a hard "drop" into gear when shifting to reverse. The first time I had the boat out after making the change was the worst. It would do it mostly into reverse, but occasionally into forward as well. Now, I've had it out half a dozen more times and it's tamed down somewhat. It will usually do it on the first reverse pull off the trailer and then sporadically maybe 2 or 3 more times here and there the rest of the time we're out on the lake but definitely not reliably every time I shift into reverse. It very rarely (if ever anymore) does anything adverse when shifting into forward.

I hesitate to think it's a shift cable adjustment, as I've done some quick checking and I do have exactly 6" on the shift cable from the barrel to the hole in the end guide. Although I didn't have time to go further than that and did not mess with the adjustable stud for reverse.

It also so obviously came on abruptly due to the prop change or as a result of something during the process.

Should I put the old prop back on and see if that changes anything? Or am I definitely looking at shift cable and linkage adjustments and I need to set aside some time to dig in and figure out where I'm out of spec?

Thanks for any advice!

 

[Chris1956]

You should always shift "positively" into gear. "Babying" the shift causes damage.

MerCruisers share clutch dogs with Mercury OBs. As such they have a number of projections on the forward part of the clutch dog, and matching ones on the forward gear. This helps slightly worn clutch dogs to stay in forward gear, vs two projections on the reverse side of the clutch dog and gear.

If you "baby" the shift, the projections get rounded off allowing the gears to slip. It sounds like you hit something, when the gears slip.

 

[Chris1956]

BTW- the forward gear clutch dog projections are slightly curved. When in forward, and the prop is turned faster then the engine revs, you will hear a rachet sound. This is normal.
Reverse gear locks the dog into the reverse gear. There should not be any racheting.

 

[Stinnett21]

Did the boat come with any paperwork? Wondering if you have anything that reveals when the last lower shift cable was installed. Pretty sure the 6" measurement can be right but the cable still be bad.

 

[Texasmark]

You should always shift "positively" into gear. "Babying" the shift causes damage.

MerCruisers share clutch dogs with Mercury OBs. As such they have a number of projections on the forward part of the clutch dog, and matching ones on the forward gear. This helps slightly worn clutch dogs to stay in forward gear, vs two projections on the reverse side of the clutch dog and gear.

If you "baby" the shift, the projections get rounded off allowing the gears to slip. It sounds like you hit something, when the gears slip.

Exactly. I rescued an 18' Starcraft Holiday with a Merc. I/O that had been badly abused. When I got the outdrive apart, the rear of forward gear and front of the clutch dog were just like Chris said. The problem with that is that there isn't enough material in the right dimension to stay engaged when you hit the throttle to get on plane.

 

[Lou C]

If your shift cable is starting to get worn and sticky it will delay the movement of the clutch dog which is the same as shifting too slowly. And you get ratcheting.