OMC 800 mechanical shift - POPS out of FORWARD

[gojayo]

A month ago after replacing the top gear set I put the 26' Sunrunner Chev 305, OMC Stringer 800 back in the water. Leaving the dock the first time it popped out of forward on hard acceleration ONE time, then all was well. This was with a 15-1/2x13 prop. Two days ago after seeing WOT RPM at 3,800 I tried the only other prop I had on the boat, a 15-1/2x19 which I thought would totally bog my boat down. But the top rev is now 4,150 or so, but it wants to pop out of forward both on the way up to plane and once at plane. Any ideas what I might be missing here? Is the 19 prop pitch putting too much torque on the gears...is the lower unit oil I used (90 weight) not perfect enough for the gears down there...I have separate shift from throttle control cables at the helm. Is there some spring detent ball that's supposed to keep the throttle in forward better? To run for 10 minutes at plane I held the shift lever with light pressure and it didn't jump out of gear.

HELP if anyone can. There are so many sharp people at this site, it's truly fantastic. Jay in Seattle

 

[studdy05]

Re: OMC 800 mechanical shift - POPS out of FORWARD

The shift cable has come out of adjustment and this is common anytime you make major changes and getting it back in alignment takes some tinkering.

This best advice I can give you is to throughly go though this. The nominal neutral is a good place to start.

But generally this means pulling the drive back off and checking those measurements in the lower. Once you get those measurements dead on, it will work right. Sounds like you are about an eighth of an inch off or so in this process in the lower:

--While rotating drive,shaft by hand, shift the unit into forward gear by pulling on the short cable Measure "A" dimension to center of puck.
--Shift into reverse gear (long cable) and remeasure "A" on short cable to center of puck.
--The mean distance ("A1"+ "A2")/2 must fall within 7-5/32 to 7-29/32" (18.2 to 20.08cm). If this dimension is not met, disassemble and repeat step 2, changing slightly the 4-7/8" starting dimensions.

As for gear oil type and prop type, I have read grumblings about others who swear by one type or another to make thier OMC work properly but I have not experienced that.

 

[gojayo]

Re: OMC 800 mechanical shift - POPS out of FORWARD

Thanks. The boat is moored now and will be a real summer disturbance to yank it now. I'm assuming the adjustment is in that box that rides on top of the lower unit when it's apart, as I remember looking at the cables and the idler pulley and all that. Is there any way to effectly "adjust" the shift cables inside the engine compartment enough to get by? Something tells me you already linked me to the neutral centering page but I didn't click on it yet.

Would the prop size or pitch have ANY effect on this popping out, or was that just coincidence?

Thanks, Jay