View Full Version : Water pump woes

01-30-2009, 11:03 AM
"Hello from Houston:

I'm new here, I hope I can learn and share. A few months ago I bought a boat with a blown engine. It has a 125 Force, 89 model Larson. I took the power head apart and completely rebuilded it, it runs like a champ. The boat had been in storage for over 5 years so I'm doing all the necesary things to get it ready for the water without having to worry about anything for awhile. Including draining the old gas, servicing the trailer bearings, replacing all seals in the lower unit and installing a new water pump.

A couple months ago, I had some time off from work and since the weather was still good, I decided to take the boat out in the lake for a test run. Before taking off, I cranked it up and made the final adjustments.....only to find out my water pump quit pumping.

Fast forward to this week. I'd ordered another water pump and installed it and within a couple minutes (on ear muffs) the pump was wasted. I took it back apart and it turns out it has traces of gear oil in it, I'd check the lower unit and is full of "milkshake".

Careful examination indicates that the only way for the gear oil to get into the water pump housing is thru the seals right under it. This 2 seals were replaced along with the rest of the lower unit seals, so......

Before I go ahead and make the same mistakes I like to know if I understand this correctly: This are 2 seals, one right under the other, a little one about 1-1/4 inch in diameter and goes on the impeller side and a bigger one about 1-1/2 inch that goes on the gear case side. The little one should go facing down? (with the spring towards the impeller) and the big one facing up? (with the spring facing the gear case). Is this correct?

Also, Should I try to flush the "milkshake" out of the lower unit? and if so, What should I use? Or should I just flush and refill?


02-17-2009, 08:47 PM
Reseal the lower unit after dissassembly and a good cleaning.

02-19-2009, 01:53 PM
"Thanks for your response Bill. My question was more to the orientation of the seals. Either way, I send it out to a shop and they re-sealed it for me. Also on their advise, I pulled the t-stat and left it out. Everything is ok now.....I think. I still need to find the time to go to the lake."

03-11-2009, 05:38 PM
Perasonally I wouldn't run it without a thermostat. Getting the engine up to operating temp will make it run more efficiently.

Good Luck!!

03-12-2009, 11:22 AM
"Use t-stats or you will just create carbon build up on the pistons, head and rings."