Stalls when shifting in reverse, also grinding sound

[lenny2113]

I have pre 1986 Mercruiser 350.<br />Everything was fine for a few times I took her out. This weekend I took her out and as I shifted in reverse to back out of the dock, I heard a grinding sound on the PORT side for about 2 seconds, then PORT engine stalled. I started it again and shifted a few times. All seemed normal, did not grind, did not stall. <br />As I was going back and came to the dock, as I shifted in reverse grinding noise was followed by PORT stall again.<br />Shift cable was not changed for at least 3 years. <br />Any ideas are greatly appreciated.

 

[jeff13601]

Re: Stalls when shifting in reverse, also grinding sound

It sounds like the shift cable could be bad causing the shift interrupter switch to kill the motor. It could possibly just need adjusting. Try shifting through the grind a little quicker

 

[lenny2113]

Re: Stalls when shifting in reverse, also grinding sound

It grinds as the shift control is all the way back. <br />If I try to play with the adjustment, could anyone tell me if I need to tighten or loosen the adjustable threaded tube? <br />Jumped shift interrupt switch, which stalled the engine, I think it ruled out the "bad interrupt switch".

 

[Haut Medoc]

Re: Stalls when shifting in reverse, also grinding sound

The shift interrupt switch is supposed to stall the engine temporarily. That's it's job. But if the cable itself is going bad it will cause the switch to hang up. The cable has to ride freely. I don't think it is an adjustment, because it would do it every time..........

 

[lenny2113]

Re: Stalls when shifting in reverse, also grinding sound

The funny part is: I replaced shift cable on the STBD side drive and was expacting that I would have a problem with the adjustment on that one. <br />Instead, it shifts like brand new without grinding or stalling...<br />Could shift interrupt be adjusted to eliminate stalling?

 

[Haut Medoc]

Re: Stalls when shifting in reverse, also grinding sound

I don't think it is. The cable is what actuates it. Why would you have a problem adjusting the cable? The merc manual has explicit instruction for this procedure. Change the cable and I'll bet your problem goes away......

 

[lenny2113]

Re: Stalls when shifting in reverse, also grinding sound

J.kopec, <br />I thought I would have had problems adjusting cable because the marina tech where I keep the boat said: "You've got to be either good or crazy trying to change the cable. It is not going to work as the adjustment is critical".<br />Still, concerned but optimistic about my ability I changed it and found it not as difficult as thought...<br />What upsets me now is that when I had the boat tested in the fall before winterizing I had no idea the other cable is bad too. As part of winterizing service I got the bellhousing inspected. They pointed out the cable on STBD side, but mentioned that PORT is good. I also had no problems with PORT in the fall. It was STBD that needed force while shifting.<br />I wish I would have addressed both cables at the same time, so that I do not need to pull her out of the water now...<br /><br />Thanks for your help,<br />Lenny

 

[Haut Medoc]

Re: Stalls when shifting in reverse, also grinding sound

Yeah well, I used to live in N.Y. and I know how cold it gets, and how long boats sit over the winter. A good idea if you can is to move the helm during the winter to keep that stuff moving. Good Luck

 

[lenny2113]

Re: Stalls when shifting in reverse, also grinding sound

I shrink wrap during winter, so no way that can be done.<br /><br />This is strange... Just came back from the marina. I played with the brass barrel on the cable thread. Adjusting it forward lost reverse, so I moved it aft and got the grinding noise smoother as it gois in reverse. It did not stall as I shifted good 20 times. <br />I took the boat out for a quick test... Backed out of dock in reverse without stalling.<br />As I was coming back and pulled into the dock, I switched to reverse to kill the forward motion, but the PORT stalled before I was able to accelerate the throttle.<br />I tested shifting again while in the dock and it was OK every time I shifted.<br />If I add just a bit more RPM it seems to shift without stalling. But it is idling at 750 RPM which is just what it should be. Adding RPM is not a solution in my book... Any ideas??<br />Forward never stalls. Only from neutral to reverse. <br />She has a mind of her own...

 

[jeff13601]

Re: Stalls when shifting in reverse, also grinding sound

Your lower shift cable is probably on its last leg. For what they cost you probably should change it. If it is idling good do not make the idle higher

 

[Don S]

Re: Stalls when shifting in reverse, also grinding sound

Your cable is worn out inside causing excess movement. Replace the cable and adjust the cable to the book, not to how you think it should be, and it will be fine.

 

[lenny2113]

Re: Stalls when shifting in reverse, also grinding sound

Don, <br />The reason I replaced the STBD cable this spring is the shift shaft bushing was allowing water to pass into the section of the bellhousing where the shift cable slide is. <br /><br />There was no noticeable damage to the PORT cable. <br />What should I be looking at as a cause of cable going bad? As I said before, the cable is 3 years old. <br /><br />Thank you!!!

 

[Don S]

Re: Stalls when shifting in reverse, also grinding sound

About 95% of the time I find that when the drive will only shift into one gear and can't reach the other that the problem is in the lower shift cable. Not much to see since you can't see in the cable.<br />I have also found problems in the other cable from the control to the engine, or the control itself. But most of the time when the cables have that much slop in them they also start binding and being hard to shift but "NOT" causing the engine to stall.