New pump and it overheats?

[Surfer]

Idle temp is about 140, but temp goes way up (220) and keeps climbing at WOT. Any suggestions, I have done the search...I replaced the external pump, flushed everything twice, got a couple of shells out of the oil cooler, but thats all, removed the thermistat, as it looked crusty. I read a thread about check balls (Yup I got em) could someone give me some info on what thats about, or what else it could be.
Thanks

[33 crossbow]

Idle temp is about 140, but temp goes way up (220) and keeps climbing at WOT. Any suggestions, I have done the search...I replaced the external pump, flushed everything twice, got a couple of shells out of the oil cooler, but thats all, removed the thermistat, as it looked crusty. I read a thread about check balls (Yup I got em) could someone give me some info on what thats about, or what else it could be.
Thanks

Surfer, I had the check balls for the water flush but with my new engines i got rid of them. What size engine is this you have and how long and hard are you running if to get the tenp to go up??????my old 454 mags used to climb in temp the longer i ran them above 3800 RPM. The new engines i run at 6000 and see no temp climb. On the new engines i did get rid of the circulating pump and went to X-over's W/ thermistats. I also run OIL thermistats.

[MOP]

There are a few possibilities. First the boat must be in the water I would disconnect the hose from the pump to the block stick in a pail at idle it should a V8 will pump a gallon every 35-40 seconds, this test will not be correct if done on a Flushette! If that looks good then go and find some "clear hose" and hook it between the Tstat housinf and the riser to see if any bubbles show in the water this test must be done underway. If the drive water grommets are leaking the bubbles usualy show up shortly after planing off, bring a buddy to watch. If the pump flow was low the impeller may have a blade flipped in the wrong direction, if bubbles show up pul drive and reseal water grommets. If non of the above when was the last time the risers were changed or cleaned and inspected. Even in fresh water they eventually will get plugged up.

Phil

[Surfer]

The engine is a Chev 350 about 1988. I run offshore at full tilt all the time. The engine never ran hotter than 140 at any RPM before I replaced the pump (the bearing let go on the old pump from vibration, I replaced the balancer and pullies, and cured the vibration, now it overheats. :kaioken: ). MOP, the risers have never been removed.

[Sierra]

Check the rotation on the new pump.



Ricardo

[Cuda]

Don't you have to "set" the bend of the vanes in the pump in the direction they need to be?

[gcarter]

Some or most of the replacement marine circ pumps have radial or stright impellors. Not very efficient but it does reduce the number of parts someone has to stock.
However if it is "handed", it will sure give you the problem you have. :smash:

[Surfer]

What is the deal with the "check balls" can someone explane?

[Rootsy]

spring loaded balls that block off flow to the risers. They can inhibit flow due to a few reasons... 1) over time they wear a groove and stick in the t-stat housng and dont want to move. 2) you overheat the motor and MELT them.. and they stick and won't actuate.. causing reduced flow through the motor and overheating...

if she stays cool at idle or cruise speed and overheats at WOT it is most likely an adequate amount of water flow issue.. weak impeller in the drive, etc. due to the amount of variables, right down to a hurt motor, it can take some time and effort to troubleshoot a merc marine cooling system... if in doubt.. start at the drive pickups and work forward...

[Pismo]

Inadequate flow, poor pump or blockage somewhere. Maybe old pump fins stuck against the oil cooler (common problem)