Grinding and stalling

[Walkers2011]

Hi everyone,
Longtime viewer, first time poster.
I currently have a mercruiser 3.0 with a alpha one sterndrive, I just purchased this boat (88 Bayliner Trophy) I started it on muffs, it starts instantly and idles very smooth, but when I attempt to put it in gear it grinds, and when I attempt to give it more gas it stalls out. I read a article I believe it was by Don, about the shift interrupter, I think both issues might be because I am on muffs and there isn't any load pressure on the prop to engage the shift interrupter, I just want to confirm this before I take it out on the water and do damage to my new love. Going through the forums it looks like I may need to adjust the shift cable or replace it also. The previous owner told me it was a cold blooded engine ( whatever that means)
1988 Bayliner Trophy
3.0 Mercruiser I/O
Alpha One SternDrive
The engine is literally brand new, about 15 hours on it and the stern drive looks like it's a freshly rebuilt one (Bayliner used OMC for the 88 trophy so someone changed it somewhere along the line) I changed all fluids to ensure it was all good and clean, I did notice the gear lube monitor in the engine was never hooked up(never had fluid in it) so I left that alone assuming it wasn't needed on this outdrive.
Hopefully I gave all info needed,
Thanks I'm advanced for any and all help guys and gals

 

[Grub54891]

Welcome to the forum! For starters, was the motor warmed up when you put it in gear? When shifting them, you put it in gear quickly or you will grind the shift dog in the lower unit. If it's stalling, maybe the cable needs adjustment or the cable needs to be replaced. Not to hard to do, read the sticky at the top of the forums for the procedures needed. As far as being cold blooded, it may be just a choke adjustment. Pretty simple thing to adjust. The gear lube monitor should be hooked up, unless the drive was changed so it did not need it. But being a fairly new motor, they could have bought a good donor motor or complete one that came with the monitor and is not used on that drive. I'm sure others will chime in on what's needed, and again welcome to I-Boats!

 

[Walkers2011]

I was going fairly slow so I may have been hanging out too long while shifting, I'll try faster tomorrow see if that clears that issue.
I forgot to mention it did idol a bit high at around 12 if I remember correctly, I'm thinking the engine may have been slapped in and never adjusted, maybe a simple carb adjustment is the issue, maybe it's getting too much gas and flooding out

 

[Walkers2011]

Ok update,
The grinding was me shifting too slow, today I slapped it into gear just a small pop which was expected, I adjusted the carb and got the idol right where it's supposed to be. It still stalled when I tried to throttle it, but noticed reverse worked great. So assumed the shift cable needed to be adjusted, as I was looking at the shift cable just to see the moving parts, I noticed 2 wires coming from the shift interrupter, I disconnected the wire and it fixed the problem. It went right into gear and throttled perfectly. I THINK it was a ground wire, I wasn't able to follow it cause both ends vanish into the harness. I tried starting the boat in gear to make sure the neutral safety was still connected properly and it didn't start as expected.
I can't for the life of me figure out what that wire was except maybe a ground wire, but it does run like a new boat disconnected

 

[Maclin]

You need the shift interrupter to take it out of gear. The interrupter stumbles the engine to unload the torque on the gears.

 

[Walkers2011]

I think it was the ground to the interrupter it was a black wire next to a purple wire both had quick disconnects, I presume the purple is a ignition coil lead, the black I got a feeling is a ground cable, I'm kinda confused on why this wire would let it go into gear but stall the boat out while throttling. I'm trying to find diagrams to think of what this wire is for sure then figure out the problem.

 

[Grub54891]

I think you found the problem. That switch is the interrupter, it cuts the ignition for a brief moment when coming out of gear . If it's not connected, it will stick in gear, and you will hit something, or someone. Either you need to adjust the cable, or more than likely you need to replace it. While you have the drive off, check alignment,bellows, and gimbal bearing. Replace all so you know where you are at maintenance wise. Also you adjust the idle, in the water in gear under load at idle. It runs a bit different than just on a hose with no load.

 

[Walkers2011]

Ok so I'll reconnect the wire, I'm going to measure and attempt a simple adjustment and see if I get lucky, if not I'll change out the forward shift cable. I THINK the interrupter is good because atleast what I pulled from other posts on this forum if interrupter was bad the engine would stall at random ( which it doesn't) so my bet is that cable. Thank you so much for the help so far guys I'll keep you updated

 

[Grub54891]

By saying forward cable, Do you mean the one from the shifter? That is not the cable you need to replace. It's the cable from the drive to the interrupter switch, That is the one that goes bad.

 

[Walkers2011]

Ok so I was checking the wrong cable then, I'll do that one then , Thank you

 

[Walkers2011]

*

 

[Walkers2011]

Ok and final update. It was the lower shift cable ( or my case upper shift cable since it was mounted on opposite side) I took off the cable, pushed it in to gear, had a buddy turn the prop counter clockwise till locked and measured it. It was sitting on 7 3/8 inches when supposed to be at 6 inches. Adjusted to 6 inches, made sure the upper shift cable was lined up correctly and that solved all the problems. It's a new engine and fresh rebuilt outdrive, so I think everything was slapped in and never adjusted properly, the carb, shift cable, some of the wiring all needed some adjusting in the end.

Thank you everyone for all the help

 

[Grub54891]

Good news! Have fun on the water!