View Full Version : Omc lower unit help!!!!

05-27-2012, 01:04 PM
i have a 1988 donzi zb22 with an OMC lower unit. it seems to lock up the engine when i put to much trim to it. is that the lower unit locking up and do i need a new one? i also cant find anywhere to get a new unit. i need some help so any advice would be great.

05-27-2012, 02:06 PM
Doubt it is the drive would be looking into gimble bearing and U-joint as possible culprits.

05-27-2012, 03:32 PM
the u-joints on the lower are good and the gimble bearing spins freely with no play also the mount on the back of the motor is good.

Morgan's Cloud
05-27-2012, 04:15 PM
Dave , can you describe in a little better detail exactly how the problem manifests itself ?

Does the unit trim smoothly and normally all the way up to down when the motor is off ?

Does it do this problem in neutral with the engine runnning if you turn the wheel hard over to hard over ?

Does it make any rattling/bonking noises when you turn hard over to hard over in neutral with engine running ?

Does it only happen in gear ?

Are you posotive that your alignment is good ?

Stuff like that would be helpful.

05-27-2012, 05:15 PM

Starting to wonder if we're using the term 'lower' the same way (see pics below). Sounds like you're using 'lower' to mean the whole outdrive (upper and lower both).

The only u-joint I know of is the one coming out of the upper.

Does your motor completely conk out if you trim the drive (up) at idle? Such that you have to trim down and turn the key to start it again?





05-28-2012, 07:44 AM
Does it die like the ignition is being cut off or does it feel like it binds up?


05-29-2012, 11:40 AM
it acts like the ignition is being cut out the motor just shuts off then it wont crank as if the motor is locked up. but there is nothing wrong with the motor or any wiring.

the unit moves up and down no problem with the motor off. it will do this in neutral but it happens every time i put it in gear. it dosent seem to matter if i turn the wheel cause it wont stay running that long but i do notice that when im trying to crank (while its acting like its locked up) it the steering will will move a little. i am unsure about the aliment. is there a way i can check that?

if i work the trim lever i can get the engine to spin and start but i have to find a sweet spot. but even if i get it to start it will idle but as soon a put it in gear it will engage start to go and then lock up.

thanks for all the help, Dave

Morgan's Cloud
05-29-2012, 12:55 PM
I think your use of the term 'locks (ed) up' is what's throwing us.

On an engine that is locked up but otherwise has perfectly fine electricals when you hit the key to try to start it , you hear the starter pinion throw and hit the flywheel. But 'cachunk' the engine is siezed , or 'locked up' .

I presume you mean that it's 'dead' when you go to re-start.

05-29-2012, 01:28 PM
yes the term had me thrown. If the motor or drive is locked up "siezed" all the playing with the trim switch isn't going to free it.
If a running motor stalls/ dies and then will not turn over but playing with a trim switch in the shifter then it turns and starts your problem is electrical, things I would look for

1. a bad ground or a ground that shouldn't be there

2. something that would kill power to the ignition/ starter circuit like your nuetral safety switch or the shift interuptor, kill switch ,

05-30-2012, 06:32 PM
Quote:but i do notice that when im trying to crank (while its acting like its locked up) it the steering will will move a little. Are you saying the steering wheel will lightly jerk side to side when you try cranking it? If that is the case the U-Joints are binding.