Where’s the water?

[Dandydan]

Volvo Penta DP C1 290 5.0FL PMDA
This is probably a dumb question but here goes anyway. I was recently running my engine on ear muffs and decided to go check out the flow into engine. I climbed out of the boat and discovered there was no water coming out of the exhaust ports. I immediately jumped back into the boat and shut it off. The temperature gauge when I shut down was just starting to get above what is normal. My first thought was that the raw water pump impeller was shot needing replacement. No big deal, it was due anyway. Ordered the part and pulled the pump and did the replacement. I discovered the impeller was worn but not broken or disintegrated. So I got to thinking, why no water coming out of exhaust ports. I decided to check if water was getting to the pump so hooked up the muffs again and watched as my wife turned on the water. No water getting to pump. Next I disconnected the hose from the fitting just inside the transom shield and turned on the water again. No water coming in. After reconnecting the hose to transom shield fitting to power steering oil cooler

 

[Scott Danforth]

First, are you plugging the lower pickup hole when using muffs?

Second, is your hose on full? You need a fair amount of pressure to get water thru the drive and plumbing. A 5/8" or 3/4" hose should be used. There should be water spraying out the muffs

Third, when was the last time you back-flushed the PS cooler?

 

[Dandydan]

Thanks for the quick response. No, I have never closed the lower hole. So just shove a slightly tapered dowel up there? I looked at the incoming side of the PS cooler and it looks great. When I rebuilt motor going on two years ago it was fairly plugged up. Still looks good after I cleaned it up at that time. So I’m wondering if there are certain trim tilt and steering positions that might inhibit flow? Thought I might try raising and lowering outdrive and turning it while water is running to see if there is is a kink some how. I can’t see anything now.

 

[Dandydan]

We do have really good water pressure here. I had to buy a pressure reducer for my salt away kit. I think i wrecked the dispenser first try.

 

[Scott Danforth]

yes, a tapered cork works, the end of a permanent marker works as well

there is no trim position that inhibits flow

the power steering cooler tubes are smaller than the inlet strainers on the drive. so technically the PS cooler is a really good strainer.

hose needs to be on full. the water pressure at my house is 100 psi, I get about an 8 foot spray from the muffs until the motor is started

 

[Scott Danforth]

also, you need to look at the raw water inlet casting bolted to the top of the H-frame swivel. they last about 2 years in salt water and about 5 years in fresh water (there is a lot of zinc in the casting)

 

[Scott Danforth]

im refering to this casting https://forums.iboats.com/forum/eng...-series-290-water-inlet-casting-permanent-fix

 

[QBhoy]

Hi
Ive often responded to a post like this with particular reference to the DP VP.

it really is a hit or a miss if these things manage to take water up effectively from muffs. I know of only one time I ever tried out of many that it actually worked. They just don’t do it well at all.
the answer to this is to pull the hose off before the water pump on the engine, then stick a hose down it before the pump. Always works.

I once even tried a large container filled with water and submerged to half way up the drive. Still didn’t work. They need a real head of water pressure, really tight muffs (even then it’s unlikely), or best of all, pull the hose before pump and get the hose down it. The latter is 100% successful.

 

[Scott Danforth]

much easier to get the right muffs for a VP 290 variant

the large container wont prime the pump unless you get the whole boat in the container.

 

[QBhoy]

much easier to get the right muffs for a VP 290 variant

the large container wont prime the pump unless you get the whole boat in the container.

For sure. The large container doesn’t work at all. These drives normally sit submerged in 3 foot of water pressure.

I had the right muffs and only remember them working once.

 

[Lou C]

And some of the muffs made now are too stiff to fit right on the lower unit. I found the Merc/Quicksilver round ones with the rod clamp work well. They are soft enough to flex so they will seal enough

 

[QBhoy]

And some of the muffs made now are too stiff to fit right on the lower unit. I found the Merc/Quicksilver round ones with the rod clamp work well. They are soft enough to flex so they will seal enough

Lou. That’s the very ones I used. The local mercury guy actually said these are the only ones he knows of that have worked with him. If you mean the ones with the metal long pin that runs through the intake and through the other side. Still use them now for my big gearcase outboards and alpha one. Work great on them too. Even got them to work on a bravo 3 revently.

 

[Lou C]

Yep those are the ones!

 

[Dandydan]

Thank you all for the responses. Here is what I ended up doing. I took the hose connection off the H frame and found out it was spotless. It was the plastic type someone mentioned. I blew compressed air down the tube and found a “normal” amount of flow. In the end I ended up plugging the lower hole with a dowel, duct taped the muffs to the intake ports and turned the water on full blast. Then I got full flow up to the port the hose connection bolts to. I guess that I need to do the taping thing to be assured I have water to the new impeller. Funny that the muffs I have been using for two years just started being inadequate for the job. Someone said that there is no way you could have a container of water under the outdrive that would work. I thought about building a wood box for that purpose but maybe I won’t waste my time. Thanks again everybody. I will try to post a picture.

 

[Scott Danforth]

Don S has mentioned duct taping muffs many times prior to his passing.