Whine at low rpm

[cleanEG]

2000 Glastron Volvo Penta 5.0GL w/ SX-A outdrive. Recently had full service, replaced gimbal, bellows, ujoints, drive shaft, plugs, impeller, water pump, all fluids, etc. Took the boat out this weekend for the first time since work was done and after it warms up, if I idle in gear or cruise slowly, it makes this whining sound. At 1200 rpms it goes away (or I dont hear it anymore at least) Here is a short video clip with the sound I am talking about:

I was going to pull the belts off and test the pulley bearings, any other ideas? Thanks for your help, first time boat owner....

 

[cdiltz13]

Re: Whine at low rpm

I have a similar issue with my 5.0 GXI right now. I used a metal crowbar (can use stethoscope, long screwdriver, etc.) to (carefully) touch various components and isolated the noise to the water circulation pump (not the raw water pump). Boat is currently in the shop for drive service so I'm going to have them look at this while it's in, but you might want to do the same to at least identify where the noise is coming from specifically. I suspected something in the cooling system since my whine didn't begin until the temp got to 170ish and the thermostat opened.

 

[cleanEG]

Re: Whine at low rpm

I have a similar issue with my 5.0 GXI right now. I used a metal crowbar (can use stethoscope, long screwdriver, etc.) to (carefully) touch various components and isolated the noise to the water circulation pump (not the raw water pump). Boat is currently in the shop for drive service so I'm going to have them look at this while it's in, but you might want to do the same to at least identify where the noise is coming from specifically. I suspected something in the cooling system since my whine didn't begin until the temp got to 170ish and the thermostat opened.

I'll take a look at the cooling system as well. I've had it on the muffs and while idling, I get no issues even after it is warmed up. Of course I didnt try putting it in gear while on the muffs so I'll have to plan another trip to the lake for some more testing....

 

[mtymax]

Re: Whine at low rpm

i have 2006 Volvo 5.7 GI-F - had same whining noise at idle or low speed... it sounds like your fuel pump. i had mine replaced and the noise is gone... $700 fuel pump though... first make sure you change the fuel filter enough...

 

[cleanEG]

Re: Whine at low rpm

Thanks Guys for the input -- I took the belts off today and after spinning the circulation pump pulley I could hear it making the same noise, although not as pronounced when the engine is running. I could also see a small water leak near the shaft seal indicating that it's overdue for replacement. I just ordered a Volvo OEM circulation pump and gasket kit. I'll update the thread when I get it installed.

 

[cleanEG]

Re: Whine at low rpm

Alright -- replaced the circulation pump with an OEM Volvo pump. Took the boat out to the river for a test run. No more leaks from the shaft seal, but after running the boat up and down river for an hour, the noise is back. I took some video this time with the engine cover lifted on the water that I will post later. In reverse, idle, or forward it will whine. I cant tell where it's coming from because it is very pronounced and loud. I checked the belt tension again and it's within spec. Is there something else in the cooling system to check?

One other thing I noticed is the volt meter when the boat is idling and/or running is showing a little less than 12 volts. Shouldnt it be showing 14 with the alternator running? I'm also suspecting that I could have a bad alternator that is slipping.....

Thanks!!