ezeke said:Your model number indicates that your motor is 20 inch. Please confirm.
The number of splines on your propeller, and/or propeller shaft, would indicate the diameter of the shaft. Normally, this model came with a 13 spline prop and prop shaft- not the V6 gearcase, which has a larger, 15 spline. Please confirm.
Based on that information, someone might have a chance of assisting you.
Dhadley said:
61fish said:How can you tell the size and pitch of the prop?
ezeke said:Your model number indicates that your motor is 20 inch. Please confirm.
The number of splines on your propeller, and/or propeller shaft, would indicate the diameter of the shaft. Normally, this model came with a 13 spline prop and prop shaft- not the V6 gearcase, which has a larger, 15 spline. Please confirm.
Ezeke,
I measured from the top of the gearcase to the bottom of the powerhead casing and it is about 15 or so inches which leads me to believe it is 20' shaft...what do you think?
I also counted the splines, there are 15 total. the prop says 14 1/2 X 19. This came with the motor and I have never ran it in open water yet.
What do you think?
Bill
Based on that information, someone might have a chance of assisting you.
ezeke said:I think that you have the 20"., measured roughly from the top of the anti-ventilation plate to the underside of the transom bracket where it sits on the transom. That is good, because you have a lot of gearcases available.
The 14-1/2 inch diameter prop will not fit on the smaller gearcases with the 13 spline propshaft, so if you want to keep using that prop, get the larger gearcase. If the prop is not that good, it won't matter.
The larger gearcase have different gears, depending on what motors they were used on, but most of the larger V4 units were 12:27 or .44.
I have two V6 gearcases, one from 1990, the other from 1991; both have 14:26 or .54 gears. You have to allow for that difference in selecting propellers, so try to find out as much as possible before purchase.
The V6 shift rods don't fit my V4 motor, so they probably won't fit yours either. Fortunately they are easy to switch, so it only matters if you don't have a good shift rod now. I have been trying to find a spare 25" shift rod for a V4 for 3 months, now so be aware that they are not instantly available, and that they want $70 for a new one.
DHadley is a veteran with these motors and a professional, so pay attention to his advise, as it is far better grounded than mine.
My biggest mistakes in switching gearcases were getting the wrong shift rods [even though I specifically asked for the correct ones] and assuming that I would be able to use the valuable propellers that I had.
ezeke said:Re. Bullet: The diameter of the rounded section of the gearcase.
Re Gears: Turn the driveshaft 27 revolutions, count the times the propshaft turns. Better to have someone else count, or put a string on the propshaft and count the coils. The specifications page in the service manual or the owner's manual gives what it should be.
I think that it will be far far easier and cheaper to find the 20 inch 13 spline unit and prop it correctly, but check around.
http://cgi.ebay.com/ebaymotors/OMC-...439QQitemZ280093820052QQrdZ1QQsspagenameZWDVW
