Fuel Pump water cooling output hose

[greenhut]

Boat 2020 Cobalt R5
Engine: Volvo Penta V8-380-CE-M

Pulled in some sand recently for a brief and mild overheat. Towed in, flushed, and no more overheat - normal operating temps.

Soon after noticed the dreaded VP fuel pump whine. Became concerned that some sand still blocking the raw water cooling to the fuel pump (most of the engine cooled closed loop).

• Opened, drained easy drain, Closed.
• Pulled hose pictured and blew back through it. Some resistance, then cleared, then heard bubbling down in the fuel pump/easy drain area. Then sucked on the hose and easily pulled lake water through.
• Briefly ran engine with hose disconnected and confirmed solid flow. Did note exhaust air pressure coming from fitting on the elbow. Guessing the water pressure typically exceeds the air pressure.
• Reconnected, ran the boat, and didnt notice whine, but not enough testing yet.

My Question - is the highlighted hose #27 the output from the fuel pump? I found it nearly impossible to trace back to the fuel pump with too many components in the way.

thanks!

 

[muc]

Boat 2020 Cobalt R5
Engine: Volvo Penta V8-380-CE-M



My Question - is the highlighted hose #27 the output from the fuel pump?

Per engine Workshop manual #47706051 Yes it is.

Might want to think about back flushing the heat exchanger. Here is what Volvo has to say about this.

Heat Exchanger, Cleaning
The heat exchanger is not serviceable. If the heat
exchanger is suspected to be clogged or flow
restricted, switch the inlet and outlet hoses on the raw
water system and back flush the heat exchanger.
NOTICE! Make sure to reconnect the hoses correctly
after the procedure.
If the water is heavily contaminated where the boat is
operated, consider installing a sea water strainer kit.

Now I should say that I don't agree with the service manual.
We have had pretty good luck with removing the heat exchanger and servicing it.
Here is a good you tube link ------ https://www.youtube.com/watch?v=D8IMTj-_zy0&t=25s
Because this is a 6 pass heat exchanger, I'm not sure back flushing will work real well. ----- it hasn't for us with weeds-----But if I was going to try that. I would remove both hoses and use a garden hose and adapter and back flush into the bilge. That way you will be able to see what comes out. And not blow any crap into the exhaust manifolds.
If you do attempt to disassemble it. Be careful. If you mess up, replacement cost is $1600.00 and no parts are available.

If you think something like this might happen again, I highly recommend Volvo's sea water strainer kit.