Mariner/Yamaha 2HP 2 stroke - parts

[Beneteau381]

My point is that a 1988 model has the water pump on top of the gearcase , driven by the vertical drive shaft. Its not behind the prop on the prop shaft

Its an awkward one because you cannot just drop the gear case,unbolt the pump cover and slide it and the impeller up the shaft. The shaft has to be withdrawn so that the impeller can be slid off the bottom and that means removing the circlip to release the shaft

I understand that the shaft is a square drive and that they should slide off the drive from the gearbox. Thats what mine did eventually. After I showed it the propane torch! I note that the Mercury of the same year is different with the pump where I said it was

 

[Beneteau381]

I understand that the shaft is a square drive and that they should slide off the drive from the gearbox. Thats what mine did eventually. After I showed it the propane torch! I note that the Mercury of the same year is different with the pump where I said it was

In fact the Mercury and Mariner of the same years are different which makes the generally accepted wisdom out of date! Mercury Outboard, Mariner & Mercruiser Parts Online & For Sale | Crowley Marine

 

[eddystone]

Seem to have written it off now (in economic terms). Had to use some force to remove drive shaft from the leg in the process broke the top of the water feed tube that runs alongside the drive shaft. The latter incidentally refuses to separate from the gearbox housing and will not turn. Also, the bolts holding the water pump housing refuse to budge. Will sell for parts - at least the power head works - just needs carb and float chamber cleaning out.

 

[Beneteau381]

Seem to have written it off now (in economic terms). Had to use some force to remove drive shaft from the leg in the process broke the top of the water feed tube that runs alongside the drive shaft. The latter incidentally refuses to separate from the gearbox housing and will not turn. Also, the bolts holding the water pump housing refuse to budge. Will sell for parts - at least the power head works - just needs carb and float chamber cleaning out.

View attachment 94746View attachment 94747View attachment 94748

My water pipe did the same, I silver soldered it. That tube has the drive shaft inside if the same as mine, did it come out of the power head ok? Where are you? Give us a bell 07967313792

 

[eddystone]

Silver soldering bit outside my skillset and facilities! Even if I could get replacement water tube based on previous experience with another example of these engines I would have less than 50% chance of getting all to join up so will sell for parts or repair. I've also damaged some of seals. Basically haven't got the time and I've got problems with my regular 2.3 Honda to sort out .
Thanks to all forumites for help

 

[VicS]

My water pipe did the same, I silver soldered it. That tube has the drive shaft inside if the same as mine, did it come out of the power head ok? Where are you? Give us a bell 07967313792

The drive shaft is not inside the water tube, It is inside the driveshaft tube
The water tube is the small diameter tube which takes the water from the pump to the power head The first of Eddystones pictures shows it and how he has broken it
The diagram below is snipped from the parts diagrams

it is not now avaialble as a replacement part but could be repaired or probably even made without difficulty

 

[Beneteau381]

The drive shaft is not inside the water tube, It is inside the driveshaft tube
The water tube is the small diameter tube which takes the water from the pump to the power head The first of Eddystones pictures shows it and how he has broken it
The diagram below is snipped from the parts diagrams

View attachment 94755 it is not now avaialble as a replacement part but could be repaired or probably even made without difficulty

That tube refers to the big one. I know what the water pipe is, as I said, I silver soldered mine when it broke

 

[Beneteau381]

On some of theses engines, there is a solid drive shaft with a square hollow end that fits on the crankshaft and on the gearbox pinion shaft. They rust and stick on which prevents the gearbox coming off. On some of them these shafts are covered with a thin metal tube which I presume is to keep exhaust fumes off the seals and bearings. This 22mm tube fits in to a specialised seal at both ends. The water pump tube, about 6mm, is brass and also sticks in the rubber seals. All this drive shaft rusting and seal sticking is what prevents the gear box and water pump coming off the leg. Things break as you force them apart, as the OP has found out and I did. It is not necessary to take the pinion and its circlip off in an ideal world to drop the gearbox. However when it is stuck/corroded, needs must. I silver soldered my water pipe and replaced the shaft tube with some 22mm tube. It now works fine and is easily dismantleable. I have offered to repair the ops stuff for a modest sum if he can get it to me. It is similar but not quite the same as mine. It would appear that yamaha and mariner were close together in the early days and then mariner and merc morphed more together later!

 

[VicS]

On some of theses engines, there is a solid drive shaft with a square hollow end that fits on the crankshaft and on the gearbox pinion shaft. They rust and stick on which prevents the gearbox coming off. On some of them these shafts are covered with a thin metal tube which I presume is to keep exhaust fumes off the seals and bearings. This 22mm tube fits in to a specialised seal at both ends. The water pump tube, about 6mm, is brass and also sticks in the rubber seals. All this drive shaft rusting and seal sticking is what prevents the gear box and water pump coming off the leg. Things break as you force them apart, as the OP has found out and I did. It is not necessary to take the pinion and its circlip off in an ideal world to drop the gearbox. However when it is stuck/corroded, needs must. I silver soldered my water pipe and replaced the shaft tube with some 22mm tube. It now works fine and is easily dismantleable. I have offered to repair the ops stuff for a modest sum if he can get it to me. It is similar but not quite the same as mine. It would appear that yamaha and mariner were close together in the early days and then mariner and merc morphed more together later!

I did not say it was necessary to remove the circlip and pinion to drop the gearbox
BUT
in the OP 's engine the water pump cannot be removed unless the drive shaft is also pulled from the gear case. The circlip has to be removed from the end of the drive shaft in order to do this

 

[Beneteau381]

I did not say it was necessary to remove the circlip and pinion to drop the gearbox
BUT
in the OP 's engine the water pump cannot be removed unless the drive shaft is also pulled from the gear case. The circlip has to be removed from the end of the drive shaft in order to do this

Vic, stop it. Calm down! I didnt say you did! I just stated what is necessary, what stops it, to drop the box. Once its off then other things have to be done