Need to know outdrive gearing

[treeeman00]

I have a omc cobra outdrive on a 87 bayliner trophy. I bought the boat without an outdrive and bought a used rebuilt outdrive from a guy that said it was off a 350 chevy. The boat originally had a 305 but I switched it out with a 350. I took the top cover off of the outdrive and counted the number of teeth on the pinion gear. It was 21. My question is I want to make sure I have the right gearing for my 350.

 

[jerryjerry05]

Re: Need to know outdrive gearing

Any other #s or stickers or anthing engraved on the case or gear set?.Possible on the front yoke boss.
Metal tag on the portside under the trim ram??
Ratio's:5.0 1.50 rev will result in 1 rev of the prop
5.7 1.41 rev will result in 1 rev of the prop.
5.0=21:17 5.7=21.16.
983843=5.0
983844=5.7

 

[Levinz11]

Re: Need to know outdrive gearing

Gearing should be in the 1.50 range. Turn the input shaft and count how many times the prop shaft turns.

 

[Levinz11]

Re: Need to know outdrive gearing

Good info here...http://forums.iboats.com/omc-i-o-inboard-engines-outdrives/help-identifying-my-outdrive-611997.html

 

[treeeman00]

Re: Need to know outdrive gearing

So all I have to do is turn the driveshaft 1 complete revolution and count how many times the prop turns?

 

[jerryjerry05]

Re: Need to know outdrive gearing

Yup try it.

 

[treeeman00]

Re: Need to know outdrive gearing

sorry for the late response but I just got around to checking how many times the prop shaft turns to 1 revolution on the pinion gear. Ok so my pinion gear has 21 teeth and 1 full revolution of the pinion gear and the prop turns 1/2 a turn. So what does this mean?

 

[treeeman00]

Re: Need to know outdrive gearing

anyone? I need to know by Friday before I take it for its maiden voyage.

 

[treeeman00]

Re: Need to know outdrive gearing

anyone.....???

 

[Maclin]

Re: Need to know outdrive gearing

One turn on the input shaft and 1/2 turn on prop shaft is 2.0 to 1.

Turn the input shaft 2 full turns, or more. More turns = more precision.

 

[treeeman00]

Re: Need to know outdrive gearing

oooh that's not good to hear! its supposed to be a v8 gearing of 1:41. I will try it again I guess and hope for the best. Thanks for the reply