anybody experience with Merc 7.4mpi

[rondds]

it's nuts to replace just the impeller in those crappy plastic body pumps

Frank's right. For the extra $50 or so in parts and MAYBE extra 15 minutes in labor, buy the whole assembly kit. OR spring for about $500 and buy the Jabsco solid bronze replacement water pump - then you can just change the impeller each time.

http://www.overtons.com/modperl/pro...cname=Water-Pumps&aID=23J&merchID=1009&r=view

 

[fc3]

Frank's right. For the extra $50 or so in parts and MAYBE extra 15 minutes in labor, buy the whole assembly kit. OR spring for about $500 and buy the Jabsco solid bronze replacement water pump - then you can just change the impeller each time.

http://www.overtons.com/modperl/pro...cname=Water-Pumps&aID=23J&merchID=1009&r=view

That's a very nice pump, but it only works with the ancient engines that do not have serpentine drive belts. I've talked to the Jabsco factory reps about the problem. They agree that it would make sense to make a replacement for the Merc plastic pumps for modern engines with serpentine drive belts, but I still have not seen it.

 

[rondds]

It fits my ancient engine!
If the actual bearing ever went, I'd probably replace with this puppy. Merc gets (I think) more than $400 for a replacement and your still wedded to the plastic housing thingy.

(I wish I had a serpentine belt!)

 

[fc3]

A kit to repair the Merc pump is about $100. Doesn't take too many fixes to make the Jabsco make sense. The Jabsco site no longer states that the pump does not work with engines having a serpentine drive belt. Hmm. Maybe they did update it.

Best regards,
Frank

 

[rondds]

This thing lists for $483.00 - shop around and you'll get it for around $425. It can also be rebuilt but I don't know if there's a kit for that.

 

[4sure]

I had the exact overheat condition with my 1999 27' Sea Ray Sundancer with the 454, this weekend. I did all the things you did, inspect the inside of the manifolds and elbows, thermostat, however my problem was a blockage from the drive to the pump. I changed my water pump with a kit last year, changed the impeller again this year. We ran a dock hose from the pump out to the drive and flushed it out, the volume of water improved a lot. Now the difference in the elbow temp, port side 112 degrees, starboard side 200 degrees, engine temp 175 degrees. From what your tech says this is a normal condition. I feel much better. What is your engine temp now?