motor shaft

[fishsalot]

guys i brought a 72 25 hp long shaft my boat is set up for a short shaft what should i do

 

[ben2go]

Build up the transom or buy an outboard bracket or jack plate.Just remember to keep the motor's cavitation plate 1 to 1.5 inches below the bottom of the transom.

 

[bassboy1]

Find you the shift rod and driveshaft off a shortshaft motor. That motor was set up so that the difference in the short and long shaft motors was a 5 inch extender in the middle. This thing easily unbolts, and with the replacement of the shift rod, drive shaft, and usually one bolt, you can convert it. However, finding these parts may be tough, and given the effort needed to find such, coupled with the prices you might have to pay, you may find it cheaper/easier to sell yours, and purchase another.

 

[Riverjet502]

This is a very simple procedure to convert a long shaft to short shaft or vis versa. First thing you do is {standing be hind the motor} on the right side of the exhaust leg you will see a little oval shaped cover with 2 screws holding it on. Remove this cover. When you look inside you will your shift shaft with a 5 inch brass block. Using a 7/16 nut driver unscrew the bolt and remove the bolt. (If it drops down don't worry you will get it when you drop the lower unit). Next move the shift lever back and forth till the shift shaft pops out of the brass block. Then you can unbolt the 5 inch extension from the exhaust housing. Might have to tap it with a rubber hammer. Then gently pull the lower unit down. The drive shaft and water pick up tube will slide out of the power head. Now you should have the lower unit and the 5 inch extension in your hands. The next step is to separate the lower unit from the 5 inch extension. 4 bolts holding it on with 1 long one on the front of the housing. Next unbolt the water pump cover note the direction of the impeller it turns to the right. Remove impeller but what for the impeller key so yu don't loose it. Now you just gently pull the 31 inch drive shaft straight out it will come. You will need a 26 inch drive shaft. Don't forget to put the "O" ring back on top of the drive shaft. These shafts are very common yet. 18,20,25 hp 1960 throu 1973 will work. Remove the 5 inch brass shift shaft extension. You will need a short shaft brass shift shaft connector. Use a tubbing cutter to cut 5 inches off the water supply tube. Then just reasemble very straight forward. I would also put a new water pump impeller in since its apart. I can do this under an hour its very easy. Hardest part will be trying to line the driveshaft and water pick up tube and the shift shaft connector all at once. Use a friend to poke a screwdriver through the exhaust house to help guide the shafts to their proper holes. Good Luck... Its not near as bad as it sounds....

 

[bassboy1]

This is a very simple procedure to convert a long shaft to short shaft or vis versa. First thing you do is {standing be hind the motor} on the right side of the exhaust leg you will see a little oval shaped cover with 2 screws holding it on. Remove this cover. When you look inside you will your shift shaft with a 5 inch brass block. Using a 7/16 nut driver unscrew the bolt and remove the bolt. (If it drops down don't worry you will get it when you drop the lower unit). Next move the shift lever back and forth till the shift shaft pops out of the brass block. Then you can unbolt the 5 inch extension from the exhaust housing. Might have to tap it with a rubber hammer. Then gently pull the lower unit down. The drive shaft and water pick up tube will slide out of the power head. Now you should have the lower unit and the 5 inch extension in your hands. The next step is to separate the lower unit from the 5 inch extension. 4 bolts holding it on with 1 long one on the front of the housing. Next unbolt the water pump cover note the direction of the impeller it turns to the right. Remove impeller but what for the impeller key so yu don't loose it. Now you just gently pull the 31 inch drive shaft straight out it will come. You will need a 26 inch drive shaft. Don't forget to put the "O" ring back on top of the drive shaft. These shafts are very common yet. 18,20,25 hp 1960 throu 1973 will work. Remove the 5 inch brass shift shaft extension. You will need a short shaft brass shift shaft connector. Use a tubbing cutter to cut 5 inches off the water supply tube. Then just reasemble very straight forward. I would also put a new water pump impeller in since its apart. I can do this under an hour its very easy. Hardest part will be trying to line the driveshaft and water pick up tube and the shift shaft connector all at once. Use a friend to poke a screwdriver through the exhaust house to help guide the shafts to their proper holes. Good Luck... Its not near as bad as it sounds....

You clearly mess with these more than I, seeing as you even know bolt head sizes off the top of your head. My memory of these doesn't go that far.

What do you recommend as far as a shorter shift rod? My experience is that a lower unit disassembly is need to replace the shift rod. What shortcut can you enlighten us on?

 

[Riverjet502]

The shift rod you currently have will work just fine. You just need to remove the 5 inch brass shift shaft extention and then install a short shaft shift shaft extention. The pic below shows a short shaft shift shaft extention. You can see it clearly still mounted on the shift shaft.

 

[bassboy1]

The shift rod you currently have will work just fine. You just need to remove the 5 inch brass shift shaft extention and then install a short shaft shift shaft extention. The pic below shows a short shaft shift shaft extention. You can see it clearly still mounted on the shift shaft.

I cannot see the picture on my school computer here, but not all of the long shaft motors have the 5 inch extension in the shift rod. Some of the longshafts that came from the factory as long shafts have the 1 piece full length shift rod. In fact, all of this style (5 inch extension style from the early and mid '70s) that I have messed with don't have the extender piece. I don't know whether or not the '72 25 horse in question is going to have the extension or not.

 

[Riverjet502]

Your thinking is correct.. The easiest way to tell what you have is if you have one of these 5 inch exhaust housing extentions bolted on. Pic below is a 5 inch extention, 2nd pic is the 5 inch extension bolted onto the exhaust housing. If this is the case then you can do as I described above. If not then you need to completely take the gear case apart and install the shorter shift shaft.. Still no biggy just an extra step.