View Full Version : RW pump issues / help needed

SWGA Boater
06-04-2013, 06:40 AM
Has anyone ever saw a new RW pump impeller that is bad? I replaced my impeller and boat seemed to run fine at idle in yard. Took to river and ran hot from start. No trash/ clogs could be found. Tried running on fake a lake. No water reach RW pump. Ok....trans cooler clogged. By passed it. Tried again. No water making it to exhaust only steam. Took out thermostat. Very little water is making it to the exhaust. Could the motor water pump be bad and not circulating water through engine? RW (new) bad and not creating suction to pull water? When I bypassed transcooler I pulled cover off RW pump. Water is reaching pump.

Any thoughts on what to try next? I have a new thermostat coming also....

06-04-2013, 07:48 AM
Did you look for an obstruction from the hull pick up to the raw water pump? Is the hose still firm or did it possible collapse on the inside?

06-04-2013, 09:10 AM
Read there are 2 different legnths of impellers for the rw pump . 1 7/8" & 2". A few boaters on other forums put in the shorter one by mistake causing poor priming and symptoms like you mention.mverify the depth of the housing and impeller legnth to make sure you didnt get the shorter one. Needs to have no end clearance to the cover and should be flush when all the way seated.

SWGA Boater
06-04-2013, 10:43 PM
Thanks for the suggestions. I am leaning toward the wrong impeller as all I did was swap for preventative maintenance. I had a hard time finding the correct one. The rw pump has been changed at some point. I talked with DIM extensively today and think I have the correct one on the way. Fingers crossed. Pump is a Jabsco/Volvo-Penta, but very similar to Johnson or Sherwood pumps. Regular Indmar impeller is what I have but DIM is stating the nonpriming is due possible to the size issue described above.

I'll update after I swap the impeller on Thursady or Friday. Meanwhile I have some electrical/rewiring to do....

SWGA Boater
06-05-2013, 11:50 PM
Pulled my newly replaced impeller tonight. Looks the same but under close inspection the new is about 1/8 inch shorter than the old--just as described above and with DIM over the phone. Fingers crossed this was causing my nonpriming/overheating issue. New impeller should arrive tomorrow or Friday. I hope it is the one that I need. Will update thread after comparing and swapping out the new impeller.

SWGA Boater
06-09-2013, 09:14 PM
New raw water pump impeller installed and worked fine. Primed right up. Hard to believe the 1/8 inch shorter pump was causing the nonpriming/overheating issue. I replaced thermostat also and I let the boat run in the yard for about 20 minutes and did not have an issues. Thanks again for the suggestions on the impeller being too short!

Now on to electrical gremlins....

06-09-2013, 10:01 PM
Gotta love this forum, eh?