8HP 4 Stroke reluctant to come out of reverse after removing lower pump case

I have an issue where when I shift from reverse into neutral (NFS8A2) reverse stays engaged for several seconds before finally giving way to neutral. Its never caused a problem because I anticipate it, but in close quarters it gets a little nerve wracking wondering how long it will stick this time. I suspect that I caused this problem a couple years ago when replacing the lower pump case (due to some corrosion). Any ideas on what I may have done during a lower pump case replacement to cause this and how to test to confirm your theory and remedy it would be appreciated. Taking the lower pump case off could have jacked up either the drive shaft position or the cam rod position a small amount. But I am going in there soon to service the water pump so wanted to try and repair the error I made last time since I will have it part way disassembled.

Any advice on do's or don'ts of removing the lower pump case to try and figure out where the alignment of things went wrong would also be appreciated. I have read some comments on other threads about not removing the cam rod bushing, but I am getting some oil leakage around the cam rod at the bushing so was considering replacing the o-rings in there which would require removing the bushing.

Any 8A2 is at least 10 years old, so it's reasonable to install a new seal kit in the LU (including the cam rod o-rings). There isn't any worry about pulling the cam rod bushing, but keep in mind that if you pull the cam rod out, you may need to pull out the prop shaft housing to reinstall it, depending on your dexterity and skill. Since you would have the LU apart to do the seals anyway, no worry. The inner o-ring replacement will call for some skill and patience.

Assuming that your whole shift linkage is not bent in any way, pulling up out of reverse should be instant, so unless the motor is at high RPM, the spring in the prop shaft should return the clutch dog to neutral very fast.

The prop shaft (and A and C gears, and clutch dog) ride in bronze bushings, so swapping the lower pump housing cannot affect the relationship of the shift cam and push rod. However, if the prop shaft is assembled incorrectly, or there is something foreign in there, (or a burr on the dog or shaft) that might restrict the return to N.

pvanv said:

A There isn't any worry about pulling the cam rod bushing, but keep in mind that if you pull the cam rod out, you may need to pull out the prop shaft housing to reinstall it

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Does having the shift rod in any particular position minimize the chance of pulling it out (F, N, R)?

pvanv said:

Assuming that your whole shift linkage is not bent in any way, pulling up out of reverse should be instant, so unless the motor is at high RPM, the spring in the prop shaft should return the clutch dog to neutral very fast.

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Have you ever seen issues with the spring? Or should it last for the life of the motor?

pvanv said:

The prop shaft (and A and C gears, and clutch dog) ride in bronze bushings, so swapping the lower pump housing cannot affect the relationship of the shift cam and push rod. However, if the prop shaft is assembled incorrectly, or there is something foreign in there, (or a burr on the dog or shaft) that might restrict the return to N.

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Most likely issue from those listed might be something foreign. Maybe I let some kind of debris go in while replacing the lower pump case. I'll see what I can see when I open it up . Thanks

jcibor said:

Does having the shift rod in any particular position minimize the chance of pulling it out (F, N, R)?

Have you ever seen issues with the spring? Or should it last for the life of the motor?

Most likely issue from those listed might be something foreign. Maybe I let some kind of debris go in while replacing the lower pump case. I'll see what I can see when I open it up . Thanks

Click to expand...

You will find that the easiest way to get the bushing out is to pop the cam rod out. Since you will want the prop shaft out to inspect anyway, no big deal. When reassembling, install the cam rod and bushing before the prop shaft, and all will fit together in proper relation. The spring is pretty robust, and usually lasts "forever". Be careful to not drop the push rod when pulling the prop shaft housing. Since you want to replace the cam rod bushing o-rings, might as well do all the seals -- get the kit.

Another potentially related issue I have is that when shifting from neutral to reverse the prop starts to spin in reverse before the reverse lock can grab the reverse lock bar, even with the reverse lock link lowered all the way to the shift rod link. If I put my hand on the cowl and just slow the 'kick' of the motor a little bit when the prop goes into reverse, even just for a faction of a second, it grabs securely. So based on this, and on the fact that it seems reluctant to come out of gear it almost seems like the shift cam is sitting lower than it should. So that maybe it engages reverse before the shift lever pops into reverse position. I think the 'popping' from gear to gear is controlled at the top end by the shift lever stoppers. Shift rod position doesn't seem adjustable. Other than looking for something unusual when pulling the prop shaft, do you have any suggestions on troubleshooting this?

The positions of the cam, cam rod, and shift rod are not adjustable. The reverse lock does not need to engage before going all the way down into reverse, as you shift at idle. Just make sure it releases in F so you can tilt. If the motor is jumping up in reverse (without the lock engaging, even though it is adjusted properly), you should look over the whole shift linkage, after verifying that the LU is all OK. Something may be bent somewhere, for example.