new impeller not runs hot

[badbowtie]

I have a 85 wellcraft with the 5.7 with a alpha outdrive I had the lower unit off so since it was of I decided to replace the impeller pump. So tonight went to the lake to try the shift cable that I installed and know when I am runing in a no wake zone for about 5 minutes the temp gets up to about 190. Then If I pick up any speed even 5 mph it will cool back down to 160. I had the boat out a week ago before I canged the impeller pump and could run through a no wake zone for 20 minutes and it would only climb to about 170-175. Any I deas on what to try.

 

[badbowtie]

Re: new impeller not runs hot

Come on guys I need some help before I head home today and pass all the marine stores just in case I need to stop and get something. I need some suggestions on what to check or try. I want to go out tom night with the boat and I am planing on going a couple places this weekend.

 

[Gary H NC]

Re: new impeller not runs hot

There was a bad batch of Sierra impellers that would fall apart when new...
If it was me i would pull it back apart.
Did you put some oil or a light coat of grease on the new impeller? Its always a good idea..

 

[Haut Medoc]

Re: new impeller not runs hot

What thermostat are you running?......​

 

[WAVENBYE2]

Re: new impeller not runs hot

Did the old impeller blades clog any of the hoses,do you get good water flow??

 

[obezag]

Re: new impeller not runs hot

When I did mine I neglected to put new o-rings in the water coupler. Ran hot. Took it back apart and replaced them and runs fine again. My 2 cents.

 

[WAVENBYE2]

Re: new impeller not runs hot

Read the forum "My wife blew up the 3.0" especially toward the end, might be helpful...Pat

 

[badbowtie]

Re: new impeller not runs hot

I did put some grease on the new impeller I did not change the o rings I was not sure were they were at or how to get to them. Any ideas when Sierra had the bad impellers. Also their was no parts of my impeller missing so the hoses should be fine I did not change any thing in the thermostat so that should have nothing to do with it. I guess I am going to pull it back apart tonight I guess I need some new gaskets again. I am going to look on boatfix and see if I can find how to change the o rings.

 

[Haut Medoc]

Re: new impeller not runs hot

Did you remove the entire drive or just the lower gear case?.....
Again, what degree thermostst are you running?.....​

 

[Gary H NC]

Re: new impeller not runs hot

The bad impellers were a recent thing.Tashasdaddy had the same problem with a brand new one.Some other members posted they did too...

 

[badbowtie]

Re: new impeller not runs hot

Okay so If I pull it all back apart and the impeller is in peices then It is bad one. I just found were it shows me the orings guess I din't take it apart far enough.

 

[Haut Medoc]

Re: new impeller not runs hot

If you did not go any further down than the impeller, you should not need to.....
Make sure that you have all of the gaskets & o rings above that properly installed......
You still have not answered my previous questions.....​

 

[badbowtie]

Re: new impeller not runs hot

I did remove the hole drive then reinstalled then pulled lower half I am 99.99 percent postive the o ring stayed while installing the upper unit if that is what you are talking about. I am not Sure what thermostat is in it but Like I said it did not run that hot a week ago with the old impeller just after last night since I installed the new impeller yesterday. So you are thinking it has nothing to do with the lower gasket were the o rings are or the o rings since I didn't change them.

 

[Haut Medoc]

Re: new impeller not runs hot

I did remove the hole drive then reinstalled then pulled lower half I am 99.99 percent postive the o ring stayed while installing the upper unit if that is what you are talking about. I am not Sure what thermostat is in it but Like I said it did not run that hot a week ago with the old impeller just after last night since I installed the new impeller yesterday. So you are thinking it has nothing to do with the lower gasket were the o rings are or the o rings since I didn't change them.

Yes, that is what I was talking about.....
I'm assuming it was always run with water supplied after replacement.....
I'd disassemble it at this point & see if there is something you missed on reassembly.....
The reason I asked about your t-stat is that 160 is still slightly warm at idle, unless it was after a run.....

 

[moser42]

Re: new impeller not runs hot

how hot should I/O motors run at?
my 4.3 mercruiser is always around 175 once warmed up, stays at that temp at all speeds.

 

[badbowtie]

Re: new impeller not runs hot

It runs 160 after I have ran 30-40 mph accross the lake for about 15-20 minutes then slow down and run through a no wake zone at idle.

 

[Haut Medoc]

Re: new impeller not runs hot

That would be normal......
You missed something when you did your impeller or you got a bad one like some of the others said.....
I'd disassemble it & look.....
It won't be as hard this time around.......​

 

[badbowtie]

Re: new impeller not runs hot

I am going to disassemble it all tonight And make sure I didn't miss anything Thanks For all the help and I will let you know what I find tonight when I pull it all apart.

 

[badbowtie]

Re: new impeller not runs hot

Well took it all apart today when I got home found that the rubber gromet that is in the upper half that the tube goes in was ripped. I started it on muffs reved it and let it idle for about 25 minutes never got more than 130 guess I will not know if it is fixed till I go to the lake tom. night.

 

[WAVENBYE2]

Re: new impeller not runs hot

My 4.3L runs a little cooler on muffs too, the water from the well is cooler than the lake water, on the lake last time (3 weeks ago) she ran 150deg. steady.