Extra long shaft to long shaft

[fishdeer24]

I have a 1975 Johnson 25 hp extra long shaft tiller that I'd like to convert to a long shaft. Do I need to purchase a long shaft lower unit or can I get a kit of some kind to convert my motor. I've tried a jack plate and I can't get the motor to plane properly or get enough RPM. Any suggestions would be appreciated.

 

[sutor623]

You would need to get three things to convert this motor. A longshaft driveshaft, a longshaft shiftshaft, and a longshaft gearcase extension. In order to change the driveshaft I THINK you would have to tear down the gearcase to get it out, and then put her back together with the proper shafts. If you did that, you would need a new gearcase seal kit to change out all the seals.

You may be able to cut the copper water supply tube down. If not you'd have to pull the powerhead to change it. There is a grommet and flange that hooks around the top and cannot be removed with the powerhead on the midsection.

Can you send us some pictures of the motor mounted? From the rear and especially from the side. You can build the transom of the boat up (like a jet boat transom) if the jackplate doesn't lift the motor high enough. Let's see some pics before we tear down the gearcase!!!

 

[fishdeer24]

I bought the boat and motor as a package (used). The boat is a 1995 Lund 14' with floor and all the options available at the time (20" transom". I'm sure the original motor was replaced with this one. The extra long shaft has the extension piece which is 5" long. Is it a possibility that someone put an extension kit in it and if they did, what did it contain? I'm not an expert on outboards but I can find my way around if needed. Why would I need a long shaft gearcase extension?

 

[sutor623]

Measure that extension piece. If it is 5" then you do NOT need to add anything, just take it away.

 

[ondarvr]

If the 5" extention is an after martket Bay Kit brand you can just remove all the extention parts and you have a long shaft. If this is an extra long from the factory you need to find the shorter long shaft parts to do it.

 

[oldboat1]

Measure the shaft of the motor. Needs to match the transom, which you measure at 20". Transom measurement would be from the motor mounting point, down to the bottom of the hull (not the bottom of the keel, if there is one). Similarly, the length of the motor leg is measured from the point where it rests on the transom to the top of the anti ventilation plate, sometimes called the anti cavitation plate -- the broad horizontal plate. The plate sits about even with the bottom of the boat.

An extra long (25") shaft would be kind of a rare duck on that motor, I think, but might be wrong. Sailmaster models in 9.9hp had the 25" shaft -- can tell by looking at them by the 10" extension (and an extra vent plate).

 

[fishdeer24]

Thanks for all of the responses!
The lower unit is Johnson green and so is the 5" extension piece.
It will be my project this winter while in the garage keeping the woodstove going.

 

[sutor623]

Well thats the issue, I dont think you have an XL shaft. I think you have a 20" shaft. So you are actually trying to convert from long shaft to short shaft (15").

 

[hardwater fisherman]

What is the model number of that motor? You say you cant plane and cant get rpms. Is it running on both cylinders?

 

[fishdeer24]

The motor is an extra long shaft. It was measured at 25". No doubt about it.

 

[fishdeer24]

I had the motor in for tune up and everything checked out and the fuel pump was replaced. It's running on both cylinders.

 

[sutor623]

Whats the model number?

 

[oldboat1]

both model # and pic would be interesting. sounds like a factory long shaft (20") with a 5" extension. Could use one of those brass extenders for the shift rod connector, and rig a water tube extension. Not sure about the driveshaft, but maybe a 25" shaft to fit. Used to make driveshaft extensions for some of the larger ones, I think. Curious (maybe a kit to work, OEM or aftermarket).

(thinking of what might have been done to create an XL shaft. understand you want to move in the other direction....)

 

[fishdeer24]

I will get the model number and photos this weekend and post it on Monday.

 

[fishdeer24]

Here is some photos

 

[fishdeer24]

Model number is 2575RLB

 

[racerone]

Why do you want to argue ?------The motor was never offered as an extra long shaft.----It is just a long shaft at 20 "-------Simple conversion and the long shaft just pulls out of the lower unit and the short shaft just slips in too !!!!!!!!---Most outboard techs could swap this in about 1/2 hr on a fresh water motor.

 

[fishdeer24]

Did you notice that I have a jack plate in which the motor is mounted on?
The transom is a 20" transom. The jack plate is 5" higher than the transom.

 

[racerone]

Why do you want to argue with motor designations that were established some 60 years ago ??-----Your motor is a longshaft and NOT an extra long shaft.----Accept the fact as true !!!

 

[fishdeer24]

If it's a long shaft, why does the lower unit sit way below the hull of the boat. Lower than normal?!
The transom is a long shaft transom!! Duh!
I think someone converted it to an extra long shaft!