Inboard Motor Questions

Sugo

Petty Officer 2nd Class
Joined
Nov 11, 2008
Messages
160
I just purchased a Bayliner Capri with a OMC 3.0L and a Cobra Leg. My boat shifts perfectly, running in the driveway but on its first water test at the lake it required me to shift past neutral to get the boat out of gear. (Forward and reverse) Does it make any difference that I shifted it into reverse while the leg was not all the way down (getting it off the trailer- It was a bit stuck, must have been on there a while) Once I got home it seem to shift fine again in the driveway. I did not try trimming it all the way up and back down at the lake.
My other question is that there seams to be a bit of excess noise from the top of the head under load (during take off) Can the lifters/rockers be adjusted on this motor ?
Otherwise the motor has 155LBS compression on all 4 cylinders does not burn any oil. (Raw water cooled if that matters)
Also what would be the symptoms if there is any water in the fuel or the fuel is really old (It does not smell old). I am going to pump it all out to be on the safe side anyway. The previous owner said it was new but he proved to be dishonest about a few other issues on this boat.
I know the are lots of questions, but any info would be greatly appreciated.
 

Bondo

Moderator
Staff member
Joined
Apr 17, 2002
Messages
71,133
Re: Inboard Motor Questions

Ayuh,... 1st off,... You have an I/O, not an inboard,... OMC at that..
Next, your shifting problem is Probably the Lower shift cable needs replacing...
And,... lastly,...
The Rattlin' you're hearing is the motor consuming it'self with Detontation...
A Tune up might fix it, or the bad gas, or timing, or.....
 

cr2k

Captain
Joined
Mar 19, 2009
Messages
3,730
Re: Inboard Motor Questions

The noise, also, could be the Gimbal Bearing. They will transmit noise through the block sometimes. But if you can only hear it from inside the boat it is probably as stated above.
 

Lodgepole

Petty Officer 1st Class
Joined
Aug 24, 2003
Messages
272
Re: Inboard Motor Questions

The noise, also, could be the Gimbal Bearing. They will transmit noise through the block sometimes. But if you can only hear it from inside the boat it is probably as stated above.

With that kind of compression, you have a good start. If you can't do it yourself, have an OMC mechanic check it out for you. Lower shift cable and adjustment, impeller, remove drive and grease gimble and u joints, pressure test drive for leaks and replace drive oil as well as a tune up. You don't know the service history and it will be worth your time not to ruin something and get caught out on the water. Service is a lot cheaper than parts for one of these.
 

Sugo

Petty Officer 2nd Class
Joined
Nov 11, 2008
Messages
160
Re: Inboard Motor Questions

I just had the bearings and seals replaced in the upper leg, the gear oil changed and a new water pump. I greased the u-joins upon re-assembly. As far as tune up. I have replaced the plug, wires, cap and rotor, points/condenser changed the oil and set the timing with a timing light.
How can I tell if the lower shift cable needs to be replaced vs. adjusted ? Does the fact that it only has issues under load point to the lower shift cable ? Does anyone have a link on adjusting the lower cable? I guess there is no way to grease the gimbal bearing without taking the leg off again ? I will pump the fuel tank dry then try it again with the new fuel before addressing the noise.
Thanks for your help guys
 

cooter2506

Senior Chief Petty Officer
Joined
Apr 8, 2007
Messages
733
Re: Inboard Motor Questions

Adjusting the shift cable is just hiding the problem it will get worse. Change the cable. Dont know if the Adults only sticky at tope of forum page has any OMC info or not you can check. If not check online for a manual for your engine and drive it will have the proper procedure for installing and adjusting new shift cable. And yes under load it will rear its ugly head.
 
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