1979 OMC 800 Tilt system

Well it's been kinda a tough year. Did a bunch of general maintenance and tuning and thought I had this boat perfect for another fun season and it did the following:

please follow my long winded story if you care.

Last four trips the same thing happened:
start great, putt around and also on plane runs with great performance for 3 or so hours. boating at all speeds, no stalling, just normal ops. Try to come to the dock and it would die when throttled down to idle. This happened repeatedly on four straight trips. I tried a different carb, that I had ready rebuilt, even went so far as to replace fuel.
Still same results. Checked timing and idle screws....etc. No change, the problem always manifested after a few hours and always seemed related to the shifting electronics.

So I went in to remove the ESA and all the wires and the ballast resistor that I installed when the breakerless mallory went in. My plan was to clean all the connections and make sure there wasn't a corroded wire or something.

Lo and behold the Ballast resistor was in terrible shape, actually the ceramic was broken in half.

Eureka, go get a new one and replace. The drive was down still from the last trip so after re-installing the ESA and related stuff I fired it up, seemed to be running great. Ready to go prove it.

BOOM! No tilt. just clicks. I think it's coincidental, and not related to the ballast resistor replacement. but?

Recheck all connections and they are good. (maybe I will do this again). Replaced one of the solenoids (up) same results. Looked at the 2 50 amp fuses and one of them looked suspect, actually had a chunk of solder on the side of it like it got hot. replaced it. same results.

This tilt system luckily has been working great for 6 seasons, but now I'm on the beach again.

The only thing I can think that was different about how I used it is that I ran it down a bit hard against the stop after last trip. I usually try to let it drop by gravity until it rests into the intermediate, but this time I tapped the switch down to get there and it thunked pretty good.

So now I need to continue to error check this thing and I'm wondering what should be my next step.

Is there a way to check the tilt motor without removing it?

Should I remove the tilt gear and try to run the motor free?

I'm pretty careful about the trunions being greased and the oil in the tilt clutch but I will verify. I'm going to take off the gear and see how free it lifts by hand.

Are there any other suggestions?

What if the down solenoid went out. Would that stop the up circuit from working?

When the motor get's ran hard to the stop what are the possible failures?

Thanks for reading and thanks for commenting.

Re: 1979 OMC 800 Tilt system

floattest said:

When the motor get's ran hard to the stop what are the possible failures?

Click to expand...

usually nothing much, but the roll pins on the horizontal shaft can break and the little roll pin bits can jam the shaft. A stalled motor might explain the solder blob you saw at the fuse holder.
New shaft kit with roll pins is $15 or so - priced as a sacrificial part.

You could also just try rapping the tilt motor with a screwdriver handle or wrench. If it comes alive temporarily, could be carbon and gunk on the brushes and copper armature bars.

Re: 1979 OMC 800 Tilt system

Howard Sterndrive said:

You could also just try rapping the tilt motor with a screwdriver handle or wrench. If it comes alive temporarily, could be carbon and gunk on the brushes and copper armature bars.

Click to expand...

Thanks Howard.

Without an assistant is there an easy way to power the motor through the 2 wire plug. I think I need to run 12 volt to either blue or green wire and then hook the black to the block.

Please excuse the lack of electrical skills.

I'm always wondering what guage wire to use in a case like this. If I run straight from battery to motor just match the guage in the harness, maybe?

Oh and to anyone who read the original post. The Boom! was rhetorical. There was no boom. just the click. maybe a bit of humm or whine, but nothing turning.

going out to take off the gear right now.

Re: 1979 OMC 800 Tilt system

Well, I took off the quadrant gear. Lifted the drive up out of the way. easy breezy one hand lift. shored it up.

key on, click the switch and motor go spinning. heyh what the.?

put the gear back on and greased it up a bit.

the drive is now going up and down as per normal. :joyous:

I guess maybe it was jammed in some way. I'll be careful and keep using her while she's eager.

no guarantees expected but it will be nice to have a little on water time the rest of the summer.

thanks for the help.