Overheating after new impeller.

[mippel]

Earlier this year, replaced stock impeller with Sierra replacement. Ran it on muffs for a half hour, it reached 175 degrees. Today, launched for the first time this year) and let it idle while i parked my truck, then idled out to the middle of the lake. The buzzer went off and the temp was at about 225. Could it be a bad impeller install, or is there something else I need to look at? On muffs there was water coming out the bottom of the exhaust bu the bottom where the lower unit attaches to the boat, but when I got home, with the gauge at 175 and muffs on, there was no water coming out of the bottom. Is there a way to check the water path once I open up the impeller housing? Is there a good way to test a impeller?

 

[mippel]

Re: Overheating after new impeller.

Ok got it home, Is tore it apart and the new impeller looks fine. Took out the thermostat housing, a little dirty but all looks good. Got the thermostat out. Will it hurt anything if I spray water with the muffs on? Then into the exhaust manifolds (i think thats what they are) to see if all is well?

 

[Don S]

Re: Overheating after new impeller.

Have a look at this overheat diagnosis file.
http://www.4shared.com/file/50572185/e88f1d89/Volvo_Penta_Overheat_Diagnosis.html

 

[mippel]

Re: Overheating after new impeller.

Well,
after replacing the thermostat and redoing the impeller. still not working the way it should. Got it sitting in a tub of water, and alarm went off again and the temp was over 200. Time to suck it up and bring it in. This is so frustrating. Grrrrrrrrrrr

 

[captmello]

Re: Overheating after new impeller.

Sometimes spending a few hundred is less frustrating than trying to troubleshoot overheating issues. Get it fixed and back on the water. Only a couple months left in boating season in our region.

I hope you'll come back and update your thread later with the solution. Good luck!!

 

[mippel]

Re: Overheating after new impeller.

Here are some numbers that i got after i shut it down while on muffs.
200 deg on risers
194 on manifolds
158 on tstat housing
162 on tstat housing by inlet hose
70 deg on impeller housing.

Oil is cool to the touch.

Could this be a sensor problem?

 

[Lou C]

Re: Overheating after new impeller.

Risers/manifolds seem hot, are you sure they are not clogged and they have adequate flow to them? The rest sounds OK....
I'd try backing the boat in the water with the plug in at a boat ramp when it's not busy and then try your temp measurement again, sometimes you will get hotter temps on the manifolds on the water hose depending on how much water pressure you have in your home water system...

 

[mippel]

Re: Overheating after new impeller.

I tried both on the muffs and in a bin with water to the plate on the lower unit. Is there a idiots guide to checking the risers? Can water be flushed into them from the hose that attaches to the tstat housing, and it should flow out the transom?

I did take off the inlet hose and run water from the motor compartment out and it seemed to flow good, I also took off the hose that ran from the tstat housing to the circulation pump and i was able to blow the water out of the thermostat housing. Also, i removed the hoses to the risers, and was also able to blow through them.

One last question, is the water supposed to flow out the exhaust outlet or the prop at all times, or only after the thermostat opens? Like by the arrow?

 

[ThreeMileBayWaker]

Re: Overheating after new impeller.

I have the newer outdrive design, but when mine is on muffs water comes out the rubber boot where your red arrow is. There is 2 small holes on both ends where it pours out of and it dribbles out of the propeller with warm water and the exhaust port above the prop.

 

[mippel]

Re: Overheating after new impeller.

Going to try one more thing before i bring it in. I still have the old impeller, and i am going to try to reinstall it. Then test everything again. At least I can say that i almost tried everything that I could think of.

 

[mippel]

Re: Overheating after new impeller.

Looks what happens in you have a working impeller. I replaced the new one with the old one:

notice flow before lower

after 20 minutes:

New numbers on hose (in lake i am guessing that the temps will be a little higher):
70 deg on risers
73 on manifolds
63 on tstat housing
118 on tstat housing by inlet hose
60 deg on impeller housing.

So off to find new Volvo impeller.

 

[Don S]

Re: Overheating after new impeller.

Looks what happens in you have a working impeller. I replaced the new one with the old one:

Sounds like you may have had the wrong impeller. What was the part number of your new impeller that didn't work?
and what is the full model number or serial number of your engine?

 

[mippel]

Re: Overheating after new impeller.

Sounds like you may have had the wrong impeller. What was the part number of your new impeller that didn't work?
and what is the full model number or serial number of your engine?

This is the one that i ordered:
http://www.iboats.com/Water-Pump-Impeller-Kit-for-Volvo-Penta-Sierra/dm/*******.000623051--**********.752952280--view_id.485799

And the part number on the box is 18-3276.

My engine # is: 4012112752
4.3GL-D

 

[Don S]

Re: Overheating after new impeller.

While that is the correct AFTER MARKET impeller kit, it obviously doesn't work. Might want to get the OEM kit 21213660.

 

[mippel]

Re: Overheating after new impeller.

While that is the correct AFTER MARKET impeller kit, it obviously doesn't work. Might want to get the OEM kit 21213660.

Agreed and already have one on hold locally.

 

[Burtonair01]

Re: Overheating after new impeller.

I had the same problem last year, the old impeller blew up and there was pieces of it through out all of my hoses causing restrictions, try cleaning out you're hoses!

 

[mippel]

Re: Overheating after new impeller.

UPDATE:
All is well. After replacing the original test impeller with the new Volvo one, it ran at about 170 degrees for about 2 hours today. That was with some high speed and a lot of trolling. So that is one less thing that i have to worry about. Thanks to all that had suggestions.

 

[wellcraft23]

Re: Overheating after new impeller.

having same problem 2000 7.4 gipwtr with sx drive. going to give this a try. using sierra part number18-301d did not work tryed jabsco part dont know part number with no success.tryed backflushing tru drive and coolers good flow. what a pain

 

[mippel]

Re: Overheating after new impeller.

having same problem 2000 7.4 gipwtr with sx drive. going to give this a try. using sierra part number18-301d did not work tryed jabsco part dont know part number with no success.tryed backflushing tru drive and coolers good flow. what a pain

Wellcraft 23,
Welcome to iboats
How was your old impeller? Was it still in one piece? I now believe that saving $10 cost me $100. So i would try the brand name impeller. It is not worth the boating down time trying to trouble shoot the issues. Good luck.

 

[wellcraft23]

Re: Overheating after new impeller.

Yes it was in one piece just dry rotted