Mercury engine coupler with OMC outdrive

[Cptnel]

Have 88 21.5ft Bayliner with 5.0 liter. Bought with cracked block(Got boat cheap)and swapping out engines. Since I use a boat maybe 30 hours a year I went the cheaper way and got a 85 305 from my junkyard. It was still running in a truck and ran well. Pulled and swapped out all the electric,carb & manifold, and starter from boat engine to car engine.Got to the engine coupler and found out that the 88 had a 3" bolt pattern on the flywheel but the 85 engine that I was replacing it with had a 3 1/2" pattern flywheel. I have a old style mercury coupler with 3 1/2" bolt pattern with same amount of splines to fit the OMC outdrive. Problem is it is one inch shorter so that the shaft from outdrive will not be completely in but over 3/4 of the way in on the splines. Has anyone done this? Opinion? And yes I know about cam difference and torque between car engines and boats as well as the spark resistant components so don't beat me up yet(ha ha ha). Thanks in advance for your advice.

 

[Bondo]

Re: Mercury engine coupler with OMC outdrive

Have 88 21.5ft Bayliner with 5.0 liter. Bought with cracked block(Got boat cheap)and swapping out engines. Since I use a boat maybe 30 hours a year I went the cheaper way and got a 85 305 from my junkyard. It was still running in a truck and ran well. Pulled and swapped out all the electric,carb & manifold, and starter from boat engine to car engine.Got to the engine coupler and found out that the 88 had a 3" bolt pattern on the flywheel but the 85 engine that I was replacing it with had a 3 1/2" pattern flywheel. I have a old style mercury coupler with 3 1/2" bolt pattern with same amount of splines to fit the OMC outdrive. Problem is it is one inch shorter so that the shaft from outdrive will not be completely in but over 3/4 of the way in on the splines. Has anyone done this? Opinion? And yes I know about cam difference and torque between car engines and boats as well as the spark resistant components so don't beat me up yet(ha ha ha). Thanks in advance for your advice.

Ayuh,.... Welcome Aboard,... While it'll all bolt together,...

With the torque loads on that union, I foresee a rather short life of the coupler,...

Grease it well, 'n Hope I guess,...

Trollin'/ displacement speeds are hardest on couplers, the constant loadin', 'n unloadin' wears the splines,...
hence, Grease it well,..

Of course, Wot starts will twist the splines badly too,...

Too bad too, ya missed the bolt pattern change by 'bout a year,...

 

[Cptnel]

Re: Mercury engine coupler with OMC outdrive

Thank you very much. Just wanted the opinion of someone with a lot more experience than me to say OK. This is the 4th boat I've had and this one will probably get the least used and least abused. May use 30 to 40 hours a year but will be with family doing a little tubing and skiing and that's about it(mostly slow easy rides). I noticed the change in bolt patterns was 85-86 so it was close.Will grease well and shift at low rpm,s.Thanks a ton for your help. Feel better bolting back in now. Take care

....and what might be the definition of short life if I'm a good boy at the helm?

 

[Cptnel]

Re: Mercury engine coupler with OMC outdrive

Ayuh,.... Welcome Aboard,... While it'll all bolt together,...

With the torque loads on that union, I foresee a rather short life of the coupler,...

Grease it well, 'n Hope I guess,...

Trollin'/ displacement speeds are hardest on couplers, the constant loadin', 'n unloadin' wears the splines,...
hence, Grease it well,..

Of course, Wot starts will twist the splines badly too,...

Too bad too, ya missed the bolt pattern change by 'bout a year,...

Thank you very much. Just wanted the opinion of someone with a lot more experience than me to say OK. This is the 4th boat I've had and this one will probably get the least used and least abused. May use 30 to 40 hours a year but will be with family doing a little tubing and skiing and that's about it(mostly slow easy rides). I noticed the change in bolt patterns was 85-86 so it was close.Will grease well and shift at low rpm,s.Thanks a ton for your help. Feel better bolting back in now. Take care

....and what might be the definition of short life if I'm a good boy at the helm?