1965 1A EZ shift gear ratio

[Fisnfool]

I'm stumped. I just counted the gear teeth of 2 out drives that came with a 1965 rebuilt Starcraft Holiday. 4 cyl inline 110. Engine serial number 1825382 and 1 outdrive has a serial number of A1831787. It has a strange gear ratio count. I marked the teeth with a crayon as I counted them. It came out to be 21 for the drive gear and 23 for the driven gear.

I have head of 20/24 so I rechecked the count twice. It is 21/23. and a short yoke

For the second outdrive, I could not find a serial number. It has 24/24. and a long yoke

The engine coupler was replace when the engine was pulled and rebuilt in 2005.

Which one of the out drives is the correct one for the boat?

The previous owner said he switched back and fourth between out drives, when they were serviced, so he would not have any down time. He did mention one ran slower that the other but could not remember which one it was.

Thanks

 

[achris]

Re: 1965 1A EZ shift gear ratio

Your counting is ok... There was a 21-23 gearset. That drive has an overall ratio of 1.84:1 (and is a '1A-EZ' drive) and is the correct drive for your engine (110). The 24/24 gearset has an overall ratio of 1.68:1 (referred to as a '1C-EZ') and was used behind the 6 cylinder 140hp engines.

That would also explain the difference in speed of the drives, both top speed and acceleration. The 1.68 drive will have a slower acceleration. You might be able to negate that with a lower pitch prop.

Chris........

 

[Fisnfool]

Re: 1965 1A EZ shift gear ratio

Thanks Chris.

You have to love this site. Ask a question at night it the U.S.A., and get a response from the Land Down Under By early Morning.

He did say one drive gave a top end about 30 mph and quick acceleration, the other was around 20mph and slower acceleration.

I'll check into props. There is a prop repair shop nearby and he can measure the pitch I have and see what can be done. I'm doing u-joints and all seals so both drives are ready. Did the 1A have a different lower gears than the 1C or are the both 1:65:1? I have not pulled the hubs yet.

 

[achris]

Re: 1965 1A EZ shift gear ratio

Thanks Chris.

You have to love this site. Ask a question at night it the U.S.A., and get a response from the Land Down Under By early Morning.

He did say one drive gave a top end about 30 mph and quick acceleration, the other was around 20mph and slower acceleration.

And will be overloading the engine by not allowing it to reach maximum revs. This is one of the quickest way to destroy the engine.

I'll check into props. There is a prop repair shop nearby and he can measure the pitch I have and see what can be done. I'm doing u-joints and all seals so both drives are ready. Did the 1A have a different lower gears than the 1C or are the both 1:65:1? I have not pulled the hubs yet.

Both units run 1.68:1 lowers...

When you find the pitches, post up here and we can see what's what....

Chris.........

 

[Fisnfool]

Re: 1965 1A EZ shift gear ratio

OK I'll post pitch when I find out. And engine load is exactly why I asked about the gears. The prop shop is closed for a couple of weeks. Note on the door says, GONE FISHING IN THE GULF, will be back May 6th.

 

[achris]

Re: 1965 1A EZ shift gear ratio

At full throttle that 110 engine should be running between 3900 and 4300 rpm. Any less is overloading the engine (at ALL throttle settings!), any more is no problem unless you are planning on running at wide open for extended lengths of time... My personnel preference is to find the 'right' prop, then go one size (pitch) smaller. It reduces the overall load on the engine, making it last longer and wear less. It also helps with boat 'driveability', and despite what people might try and tell you, does NOT use more fuel....

Chris........