Water Pump Impeller Blues

Big D · Post by **Big D** » Fri Aug 13, 2010 8:34 pm

One of the best tools in my toolbox. Never leave port without it!

Also check your hose clamps on the raw water intake hoses to ensure you're not sucking back air. Ran into this before; replaced everything only to find problem wouldn't go away. No water leaks noted but two loose clamps at the seacock solved the problem.

rossjo · Post by **rossjo** » Sat Aug 14, 2010 11:58 am

I have 2 temp guns - a cheapee , and a good Fluke - never leave without both.

As for easy - the Sherwood pumps/impellers on my Cummins are an absolute bitch - I had to make a special tool to get to one of the 3 nuts ... that helped a lot, but it was designed by someone who had never given a thought to maintenance. Its the only thing I dread doing on my Cummins.

Big D · Post by **Big D** » Sat Aug 14, 2010 12:05 pm

Ross, I have the Fluke as well, nice unit.

sehord · Post by **sehord** » Sat Aug 14, 2010 12:32 pm

and if you get bored they are great for cats and kids to watch chase around the laser dot!

Big D · Post by **Big D** » Sat Aug 14, 2010 6:02 pm

My wife would say you're sick but I like doing that too!

sehord · Post by **sehord** » Sat Aug 14, 2010 6:40 pm

Ahhhhh... Normal is just a place on the Washing Machine

rooferdave · Post by **rooferdave** » Sun Aug 15, 2010 9:15 am

while we are on the topic of heat probs on my first test run yesterday starboard runs at about 160 and port at about 180 at 2100 rpm.... when I increase engines anymore the port engine temp rockets up to 200 and climbing, slow back to 2000 rpm it comes right back down, suggestions?

Big D · Post by **Big D** » Sun Aug 15, 2010 9:57 am

Could be a few things:
- less than full flow in cooling system. This could be impellers, intake restriction, loose intake hose clamps and sucking back air, blockage in circuit such as pieces of impeller stuck in oil cooler or heat exchanger from previous impeller failure, etc.
- T-stat may be at fault, not opening up all the way
- different t-stat
- if fresh water cooled, could be impeller pieces as mentioned above blocking water passages in the heat exchanger, exchanger may need service/cleaning
- poor coolant quality
- poor oil quality
- a problem with the engine
These will get you started!! I would begin with the simple stuff first and eliminate one thing at a time then test before moving on to the next possibility. That way, you'll find out what was causing the issue for refference should the same problem arise at a later date.

sehord · Post by **sehord** » Sun Aug 15, 2010 9:59 am

Oh the joys of chasing the last few degrees of cooler water.... look back on past threads here and you'll find a ton of topics on this, impellers, clogged oil cooler, water lines sucking air, bad thermostats, clogged risers/elbows...... the bottom line is your not getting enough water flow to cool your engine. Are you raw water cooled or do you have heat exchangers? Check your impellers first, then possibly back flush your system to push any debris out. Are your sea strainers clean? are your intakes clean and allowing enough water into the system? can you see a difference in the water output of one engine compared to the other?

rooferdave · Post by **rooferdave** » Sun Aug 15, 2010 10:17 am

sorry should have said upfront engines are cooled with the lake water no exchangers. sea strainers are clear, went under boat and checked while I was changing anodes for magnisium ones, seacocks were inspected before launch, took the hoses off and visually inspected them opened and closed. Risers were inspected before install blown, out with compressed air and flushed with water. hoseclamps all new when assembling the engines and double clamped on the seacocks. The engines are 5.7 mercruisers. As this is Sunday I cannot get gaskets so I will pop the thermostat tomorrow and do the boiling water / heat gun trick. Any reccomendations where to get impellers neat Toronto without getting raped? Bob sent me my manuals but custom broker fees were 35 dollars! So I think he is out as are anything stateside

I will update when I find problem. I actually posted as I wondered that if the running fine at 2200 narrowed it down any. Thanks for the input guys and I look forward to any otherinsight

Dave

Big D · Post by **Big D** » Sun Aug 15, 2010 10:37 am

If you don't know how old the t-stat is and you're going to remove it anyway, why put one back in that may fail this or next season? When I go through the trouble of dismantling a reasonably priced item, I replace with new and record when done.

mtwolf · Post by **mtwolf** » Wed Aug 18, 2010 8:19 am

Rebuilt my pumps several years ago but didn't replace the cams. Why they are called cams beats the hell out of me when they look like back to back forks. Anyway, port engine always ran a bit hotter. Last rebuild I replaced the cams, which on closer inspection, were well worn. Now port engine runs a bit cooler but both are better. Moral of the story, you may want to check the cams also. These were the raw water pumps.

John
F-31 Trojan

pk · Post by pk » Fri Aug 20, 2010 5:42 pm

I have found a water pump without impellers. It have a metal wheel inside, running on brass bearings, water lubricated. The wheel is in exentric position, and pump water (or other fluids) much better than normal impeller pumps. It is made in Germany, and I will see if I can take a picture of it. I guess the Exenter-pump will fit in almost every engine....

rossjo · Post by **rossjo** » Fri Aug 20, 2010 8:36 pm

Exenter Pump? Is this a Viagra gag or what?

http://www.google.com/search?hl=en&clie ... =&gs_rfai=

pk · Post by pk » Sat Aug 21, 2010 7:38 am

No, sorry! It is not a Viagra pump.... Real MEN in Trojans donÂ´t need Viagra...... No, actually it is a very nice pump, made for pumping water, oils, chemicals and other stuff. The only restriction is to avoid highly flammable fluids like gas, petro-thinners, and ofcourse "boose" (moonshine). IÂ´ll try to get a picture of it, and put it here.