volvo penta cooling

[Seabass302]

I think i have a cooling problem with my 2001 VP 5.0GL with a SX-M outdrive. In January I purchased the boat with a overheated motor that tuliped a valve. I rebuilt the motor and started it up for the first time today and it ran great(only let it idle for a minute) I hooked up the ear muffs on the outdrive like normal, but I wasn't seeing any water exiting in the prop. I then disconnected the intake hose to the impellor and I still wasn't getting any water. I was able to get some water here if I squeezed the muffs against the outdrive to get a better seal. I thought it would have been easier to get water to the impellor. Do I have some blockage somewhere or the worlds junkiest muffs($14.99 at West Marine)?
To further investigate I removed the outdrive and hooked up the muffs. There wasn't any water coming from the water port near the drive shaft. So I then put the garden hose in the port and it appeared to flow unrestricted out of the intake holes I had the muffs on.
How does the cooling system work? Does the impellor create suction? I don't think i'm having any problems with the water pumps, because I can't even get the water to the impellor.
Any help would be greatly appreciated and thank you in advance.

 

[Don S]

Re: volvo penta cooling

Does the impellor create suction? I don't think i'm having any problems with the water pumps, because I can't even get the water to the impellor.

Yes, the impeller in the raw water pump creates suction and pulls the water up from the drive. It helps to have good water pressure and give the engine some rpm 1000 to1300 rpm to get the water to the pump.

Since you can't (haven't) got water to the pump, I would think the impeller may be toast also.

 

[RXWingman]

Re: volvo penta cooling

Have the same engine 5.0GL PEFS - I've searched... where is the impeller and how do you change it? Sorry if stupid question, but I've searched and only found info for impeller in outdrive and for the 3.0L engines.

Boat has been sitting for 4 years - pretty sure changing the impeller is a smart thing to do but not having any luck finding info how to change it.

 

[Seabass302]

Re: volvo penta cooling

Thanks Don, i'llchange out the impellor and give it another shot.....wingman the impellor is found in front of the crank pulley.

 

[Don S]

Re: volvo penta cooling

Wingman. read this thread.
http://forums.iboats.com/showthread.php?t=468286

 

[RXWingman]

Re: volvo penta cooling

Okay... got the rules, thanks Don!

 

[Seabass302]

Re: volvo penta cooling

Update...i replaced the impellor and o ring and I'm still not able to get the water to cool the motor. I have also taken the garden house and tried to fill/prime all the watet lines. I have tried several different muffs also. The best that I can do is if I squeeze the muffs against the outdrive ill get some water out of the exhaust, but as soon as I remove pressure the water flow out of the exhaust will stop. what does this mean? And all thoughts are welcome. Thanks again.

 

[craze1cars]

Re: volvo penta cooling

I will suspect you have a restriction somewhere. Corrosion/water deposit/barnacle buildups, etc? Probably the root cause of the initial overheat...and still a problem.

Volvo service manual specifies 24 different checkpoints for flow restriction, explains all the flow patterns, and it refers repeatedly to the flow diagrams provided in the service manual...it's far too much to reprint or try to describe here in an internet forum.

I strongly advise the purchase of a service manual, start disassembling and systematically attacking each water passage until you find and clear a blockage...

FWIW, my $10 cheapo muffs work fine on my 1999 5.0 GL Volvo SX with a garden hose. It's not the muffs causing the problem...

 

[jfpound]

Re: volvo penta cooling

This may help...

 

[JoLin]

Re: volvo penta cooling

FWIW, my $10 cheapo muffs work fine on my 1999 5.0 GL Volvo SX with a garden hose. It's not the muffs causing the problem...

Not necessarily. The 5.7GSi / SX duoprop in my '97 Chris*Craft will eventually overheat on muffs, but runs at a rock steady 160 deg in the water. The OP might try sealing the muffs to the housing with duct tape and see if that helps.

Not saying there isn't a restriction, but he indicated that he sees better results when he holds the muffs against the LU.

My .02