2005 F250 water will not go into the flush port

[Whaler22]

Recently bought a 2005 Yamaha F250 and got it hooked up today. When I attach the hose to the flushing attachment the water will not go in and flush to the lower unit. I have traced the hose all the way to the head and that’s where the water seems to stop but not sure. I can hook ears up and run the engine and it will pea. Dropped lower unit and hooked straight to water tube and water will pea but again when hooking to hose flush attachment no water comes out. Where does it go and how do I fix this? Thanks for any help! I worry that if I run it in the water something is obviously blocked somewhere and may cause overheating.

[TownsendsFJR1300]

If on muffs (with water pressure) and it's peeing (running), it shouldn't be an issue (running)….

The WP IS pumping water to the power head as it should.

How do you know water isn't going down to the LU?

[fairdeal]

since you've traced the hose,
you've seen that it runs around aft of the engine -
then goes up - between the two heads;

it attaches to an elbow on the "joint cover", just below the knock sensor.
I don't think you can get at that, without removing at least one cylinder head.

[Whaler22]

Thank you for the response - Any risk in running even know that port/pathway is blocked. I know it is as with an active hose attached to the flush port water does not flow through and backs up pressure at garden hose line with no visible water exiting lower unit. I assume it must be blocked at that joint between the heads. Anyone have a diagram showing how that line intersects with the rest of the cooling passages? Any other ideas. If I can run on muffs as stated and with that pathway blocked does it still reach the rest of the engine. Thanks again! Sorry if I am somewhat repetitive but don’t want to screw this up

[pstephens46]

Wonder if one or both thermostats could be removed and pressure from the garden hose used to backflush that block fitting?

[rodbolt17]

why not try compressed air?
sometimes the 90* fittings clog with sand.

[Whaler22]

No luck on compressed air or probing the area with wire and such. Will try all again and then thermostat option. I will report back and please keep ideas coming

[robert graham]

Maybe some kind of insect or rodent built it's nest back in there?

[fairdeal]

No luck on compressed air or probing the area with wire and such.

Have you located the double-ended connector -
where the two pieces of hose are joined near the back of the engine?

I would certainly separate the two hoses there,
see which side the blockage is on -

and if its the "engine side" - maybe from there you could snake up a monofilament








(IMO, messing with the thermostats isn't likely to help )

[Whaler22]

Great pics really gives me an idea what I am working with. Blockage is on the engine side from separation of tubing. Other side exiting through flush attachment is clear. Unable to clear blockage with trimming line/wire/etc/air compression/water pressure/vacuum - so will keep trying and if all else fails at least by design it being blocked will not hurt the engine while running. I will just have to flush with ears - maybe as it runs and gets hot things will break free. Engine had not run in about 4 months when I bought it. Again thanks for the help. I will post back if I figure it out.

[pstephens46]

Great pics really gives me an idea what I am working with. Blockage is on the engine side from separation of tubing. Other side exiting through flush attachment is clear. Unable to clear blockage with trimming line/wire/etc/air compression/water pressure/vacuum - so will keep trying and if all else fails at least by design it being blocked will not hurt the engine while running. I will just have to flush with ears - maybe as it runs and gets hot things will break free. Engine had not run in about 4 months when I bought it. Again thanks for the help. I will post back if I figure it out.

Test your alarm. If it overheats, you will want to know ASAP. Pull the safety lanyard out of clip, try to crank motor. Alarm should sound.

[HMBJack]

And, maybe take readings with an infared heat gun after running it and getting the engine hot.
This may reveal a non-issue to you since the engine pees good (some do not).

Like you said, it might clear up with usage - might not. I would try a very rich solution of salt away through the flush port.
Or better yet, put a large basin under the LU, and run the engine with a heavy dose of vinegar, salt away, and/or dawn soap.
The chemicals in the basin could loosen up the blockage when hot.

[carlitos]

I have solved overheating concerns by simply pulling the thermostats and recirculating about 4 gallons of 9% vinegar for about 3 hours to remove the salt and calcium deposits that are causing the issue. IMG_0574.jpgIMG_0573.jpg

[TownsendsFJR1300]

Some before and after pic's (internal to the engine) would be good.

Is the blockage now gone?

[zenoahphobic]

I have solved overheating concerns by simply pulling the thermostats and recirculating about 4 gallons of 9% vinegar for about 3 hours to remove the salt and calcium deposits that are causing the issue. IMG_0574.jpgIMG_0573.jpg

Yep, should be standard procedure to do this now and again, even just with warm or cold water. Relative cheap preventative maintenance.