Is water too fast through a broken pickup screen for a generator????
 

Here is the scoop. My Formula 419 has a Kohler 4K gen and it works fine anchored or in a slip. If we get on plane the gen will die with what seems to be exhaust over temp. This gen does not have codes displayed but the water impeller cover is warm when this happens so I'm pretty sure this is the case. The water pickup for the gen has two broken bars in the face/screen, whatever that area is called where the water enters the pickup. Will the broken bars make an opening that pushes too much water creating a venturi effect that pulls water from the generator strainer? The strainer is clean and it works fine unless we get on plane.
TIA

You know the pump is good because it works at idle, just make sure it's not being damaged any more because I fear it's running dry.

I'm guessing you have a basic clam shell type strainer on the bottom for the geneset? If so the bars not only act to prevent crap but act as a diffuser if the bars are gone I believe the shell will pack in so much water that it will back up, make a bubble and then a void when you get going fast enough and thus not allow water into it - if that makes sense? The bars are to maintain the shape and break-up the pressure bubble that the open scoop would make and allow for water to flow over it so the shape pulls the water into it.

Have you ever done the spoon under the faucet trick, water flowing down over the bottom side of a spoon actually pulls the spoon into the water. Since the the little strainer can't be pulled to the water, the shape pulls water to it - try the spoon trick sometime it's neat!

My 382 had the same issue, I would lose water pressure to the gen on plane. My pickup was mounted aft of the step, so I don't think it got clean water. My bars were a little dinged up too, so maybe that was it after all?

The fountain uses a transom pickup to feed both the gen and AC. This provides ample water pressure at any speed.

I did not think about the placement as an issue, interesting point. I heard back from TAG and they recommend replacing the pickup. After that is done I hope that it can get ample water to run on plane. If not I will consider plumbing it differently so that it does.

The other issue, is there is no way the AC will get water under way. I know that's not what you're after, but it does seem kind of silly to me that it's a standard through hull right under the step.

That will be another test and sounds like a fail. TAG responded back and stated that this is an issue where the aeration aft of the step will not allow enough water in the pickup for the gen to run. AAaaaaarrrgh!!! I can't believe that Fountain plumbed this the better way and Formula only built for the slip. Looks like I have some engineering to do for my Gen to run on plane.
I guess on the bright side, relocating the pickup will be much better for the trailer bunk situation. Formula placesd this inlet right in the place where trailer bunks contact the hull. This seems to be the main reason that the bars get broke out of the inlet strainer.

Fountain actually did a great job plumbing this boat. The high speed transom pickup feeds a 1.5 gallon strainer, with pressure relief, that feeds both the AC and Generator. All 3 drives feed a colossal strainer, that subsequently feeds all 3 engines. 2 strainers to deal with and all the plumbing is right in the engine compartment. If you decide to do modifications, this is the route I'd go.

I'll draw up a diagram, and or take better pictures when I make it out to the boat next.

So the pickup looks just like this one

[ATTACH=CONFIG]547825[/ATTACH]

Here is a pic of the two strainers, one for Gen / Air and one for engines.

[ATTACH=CONFIG]547826[/ATTACH]

The AC inlet is the one that will be a challenge. It is in the cabin floor below the step and that will have to reroute to the rear of the boat which could be some fun. This is what we want so it must be.
Formula plumbed the install very well for the pressure relief, feeding and operation. The prob is it is not good enough for water feed on plane. The mono hulls have no prob with this but the stepped hulls do. The broke bars likely have no impact on this situation at all.

[ATTACH=CONFIG]547827[/ATTACH]