Low speed cooling problems

[rogerwa]

I got the boat out for the first time this weekend. I noticed it ran real hot when at idle. When I bumped it up to around 1500+ RPMs it would cool down nicely.<br /><br />Is it possible the impeller is bad? Or is this not symtomatic of the LU impeller? I am going to check the T-stat first as this is the easiest, although I just tested it last fall.<br /><br />I read in some of the other posts that this is more likely the engine circulating pump. Although, don't these start to leak or weep before they go bad??<br /><br />Also read that the power steering cooler maybe a clog.<br /><br />I have an 87 3.0l Mercruiser with power steering..<br /><br />Any guidance would be helpful..

 

[jeff13601]

Re: Low speed cooling problems

I would guess that it is time to change the impellor

 

[Haut Medoc]

Re: Low speed cooling problems

What ya got? You all ready have two things that you know you have to look at.....Check 'em out and post back.......J .P.S. It's rare that the engine pump fails that way, I would not start there.........And I would post back before you do..........

 

[waterone1@aol.com]

Re: Low speed cooling problems

When was the last time the impellor was changed ? Besides the impellor, I would look at the water hose that goes from the drive to the gimbal housing, it could be leaking outside the boat and causing a loss of pressure.

 

[rogerwa]

Re: Low speed cooling problems

The impeller needs to be changed. I bought the kit last year and intended to do it but ran out of time. I guess I will take the time out now to do it.<br /><br />Couple of questions.. How heavy is the outdrive? Can I handle it myself? Also the procedure calls for Mercs PerfectSeal and Special lube 101. Are there other products that are compatible?

 

[Mahoney]

Re: Low speed cooling problems

outdrives are not heavy and pretty easy for a single adult to handle, however its not the weight but the awkwardness of the drive and how its connected. You could get it done yourself, but will be much better off asking a friend to give you a hand for a few minutes to make sure you don't bend/drop anything when removing it.

 

[rogerwa]

Re: Low speed cooling problems

The impeller was definitly bad. It was in tough shape. The job couldn't have gone easier!!<br /><br />I was able to drop the LU and reinstall myself without a hitch. Although I may need to separate the case again as i did not inspect the oil passage seal. The only problem I had was mosquitos. they were feasting on my as I as trying to get the thing back on..<br /><br />I have not run it yet but am optimistic I have solved the problem..

 

[bigdaddyofhouse]

Re: Low speed cooling problems

Did you back wash befor reinstall? All the littel peices can and will plug up the system and should be back washed out.

 

[rogerwa]

Re: Low speed cooling problems

How do I back wash?? I have done this on outboards but not sure where to do it on this motor..

 

[Haut Medoc]

Re: Low speed cooling problems

You don't need to back wash unless you turned the impeller into chunks. You could take the hose off at the ps cooler and see if anything is stuck there.Post back to let us know how you made out.........J

 

[rogerwa]

Re: Low speed cooling problems

There were a couple chunks missing, but they were not that large. I was hoping they would just pass. I inteneded to remove the T-stat anyway just to check in there for anything. I will look at the powersteering cooler if I can find it or reach it..

 

[Haut Medoc]

Re: Low speed cooling problems

Ps cooler should be on starboard side under manifold. Look for the water inlet hose from transom..........J