Tohatsu 90 water pump rebuild

[danhend]

Are there any walk through completed project posts that would help me perform the instalation of a Tohatsu water pump rebuild kit. I have removed the cowling around the top of the lower unit, and it seems like I must remove the lower unit in order to get access to the pump etc. Before I just start doing that, would love to see some pics, or at least read someone's story as to how they did it. Thanks for all your help, this forum has been great getting me started in my boating journey.

 

[danhend]

Re: Tohatsu 90 water pump rebuild

Some more background:
This motor is new to me. It seems to run great, and not get hot, but the stream is very weak at idle, it does flow better at speeds, but I am concerned that there is not enough flow, and I will eventually have a problem. So I guess 1st question, is the weak stream normal, and if not would replace water pump/impeller fix the issue.

 

[pvanv]

Re: Tohatsu 90 water pump rebuild

OK, so you got the skirt off, and can now see the castings...

In the future, it would be helpful if you posted the exact model of the motor.

To work on the WP on any of these OB's you will drop the LU. That involves removing the LU housing-to-exhaust housing bolts and (depending on model) disconnecting the shifter. The water pump is bolted to the top of the LU. Remove those 3 or 4 bolts, and the housing pulls up, revealing the impeller, which is keyed to the driveshaft.

If there's any significant wear to the pump cup or wear plate, I would suggest getting a complete pump kit, rather than just the impeller (again depending on exact model) from any Tohatsu dealer.

You may want to get a Factory service manual (depending on model and age, it's available at any Tohatsu dealer). Likewise, you can get a parts catalog that shows how it all goes together (with exploded diagrams). The catalog (depending on model and age) is available at http://www.internetoutboards.com/PartsCatalogMenu.htm

 

[pvanv]

Re: Tohatsu 90 water pump rebuild

The usual cause of a slow cooling telltale port is crud and salt accumulation in the tube or fitting. This can be cleared with a stiff wire, or a judiciously-applied blast of compressed air, while the motor is running. Then the crud flushes out.

Of course, it's possible to have a poor pump impeller. They do need to be changed periodically. Normal maintenance.

 

[danhend]

Re: Tohatsu 90 water pump rebuild

Thanks for your reply. It is a M90a 2 stroke. I was told '96, but not positive of that (Boat is 90). I already have the whole pump rebuild kit reserved for pick up this afternoon. Figured that was best, if nothing else I know when it was done last.

The fitting that attaches the hose to the motor cowling was broke, I have added an adapter and hose clamp to force the water out. Are you suggesting that I blow air in there?

 

[pvanv]

Re: Tohatsu 90 water pump rebuild

I would disconnect the tube from the block and verify that the tubing is clear, as well as probing into the nipple on the block with a stiff wire first.

You can probably get a slightly longer piece of tubing that will extend through the cowling so that you don't need the hose clamp, etc.