Generator dies when running on plane about 40mph; Why????
 

I posted in the general section also but I thought here might help Formula boaters or some of our boaters know what this is about.
My 419 has a Kohler 4K gen and it works great if we are anchored out or sitting in a slip. If we get on plane around 40mph it will die. When this happens I noticed the impeller cover is warm so this seems to indicate the shutdown is a result of exhaust over temp as a result of a lack of water. The water pickup for the gen has two bars broken out of the inlet. With these bars broke out can the water rush through so fast that it siphons water out of the strainer? The strainer is clean and there are no problems otherwise and the broken bars are the only thing noticeable with a visual inspection of the system.
What are your thoughts? Has anyone seen this before?
TIA

Why would you run it on plane?

Margareta blender was my first thought.

The only way you would be able to run the generator when on plane would be if you had a pickup that "scooped" up the water when moving forward. It sounds like you don't have this. Thus, your generator & it's install were not designed to run when on plane. When your boat is sitting in the slip, the water pressure of the inlet being about 24-30" below the water's surface is what is creating enough water pressure for your impeller to cool the system. You likely need a new impeller now as well.

If not that,

Are you lower on fuel than normal ? Does the genset use a shorter pick up tube in a/the main gas tank than what the engines have ? I know some do this so you can't run the tank out of gas..The gen will die before that happens. Particulary helpful when staying in boat for a long time (week-end / week / what have you.)

Note: I'm assuming boat's gn fuel set-ups are like many RV's. LOL. I have no boat generator experience.

Why do you need the generator when running on plane? My Sea Ray Sedan had to be at the dock or at anchor for the genny to get water to run at proper temp. If you want to use it running install a transom mount pickup or one that's designed to scoop water when running.

We do have the built in counter top blender and popcorn and movies need power you know, lol. The "scoop" that Formula installs in the boat is forward facing and is designed/plumbed so that water pressure at speed does not overcome the impeller. Impellers can not have more than 7psi or somewhere around there pushing against them so the plumbing that Formula installs allows for the inlet feed pressure to be exhausted out the discharge. All this is factory and fine as I understand it. The pickup has bars in the inlet and two of these bars/screens are broke out. I would think the result is water flow/speed that is excessive and maybe even siphons against the strainer. My impeller is new this year and only has 12 hours run time so it is not a factor I don't believe. The cover is warm when it shuts down which is what happens if a gen runs with a bad impeller because water is not pumping through. The fuel idea I had not thought of but since the cover is warm I am more concerned with water flow.
I don't have a pic but if you are familiar with the plumbing it runs straight up from the pickup with a diameter of 1 1/4" and has a "T" off to the strainer at like 1/2" line. The water column coming up is very large but the feed to the strainer is small. The dynamics of water flow have something to do here I think. A poster in the general section eludes to this and may have the best description yet.

I would replace the pick up.

Sounds like the same sort of pick up used on many different boats. Usually bronze, elliptical shape with 3 or 4 bars running longitudanly. I've had one on a Sea Ray that never failed. Admittedly the Sea Ray was a slow boat (30mph) but I can't believe Formula would fit a pick up to their top end boats that will only work at low speed. If they did, I think they would have warnings in the owner manual and stickers on the genset stating it cannot be used at high speed. Should work at 40, top speed and 'airing out' may be an issue.

RR

Yes that is the same pickup I have. I will replace it because it is broken from trailer issues that I also have to fix. Just amazing to think that two bars broke out makes all the difference but I guess I will find out.

^^^^. This is exactly what I have on my Black Thunder. It then feeds to a strainer with relief then to the Gen. I've ran the gen a few times when running and never had any issues with temp or water flow. Wish my AC pickup was the same way so I could have it running at least he same time. Mine is a Kohler 5E as info

Marc Blondin could chime in and say why he built it that way when new as my 46 just had a flush mount fitting not a scupper.

My 7K Kohler in the 350SS had a small LED read out on it and would throw a code when it stopped abnormally. I think it would read LOC (lack of cooling or coolant) when it would not get the proper water flow, which happened all the time if I tried to run it over about 25-30mph, especially if the water was a little rough. I finally stopped using it if I was going to run on plane. I would think it would be hard to keep the correct water flow on a stepped bottom boat even with a cupped pickup.

On the fuel topic, at least in the 350SS, the fuel pickup for the generator was set higher in the gas tank so that you could not run yourself out of fuel anchored out for a night with the gen running.

I just don't see that brass through hull being designed for running on plane. Maybe idling, or when sitting on the hook in a current.

I would definitely replace the pickup though if it has broken bars. If it goes back to working when on plane, let her continue to rip.

I had the same pickup on my 94 419 fastec. If I remember correctly, it is mounted downstream of one of the steps. I rarely used mine on plane, so I can't remember if it periodically shut off or not. If after you replace that scupper, it doesn't work, I would look into a transom mounted pick-up that is adjustable in height. You can then tune it to accept water at any speed. The bypass plumbing should insure there is sufficient water for the impeller to draw from without pressurizing it. I have a similar system on my 38 EC (uses a transom pick-up that serves one engine and the generator and the other transom pick-up serves the engine and the a/c unit) that works great at any speed. Fountain routes both the transom pick-up and bravo drive water inlet to a "tee" that runs to the sea strainer. Each sea strainer then serves an engine and either the generator or a/c water line. It is a pretty trick set-up that functions really well to insure all components are getting sufficient water. If you search around the forums you will see many high performance boats having issues with getting sufficient water to the engines. I think the brass scupper is so inefficient, you are seeing the same issues at 40 mph. Good luck and enjoy that 419. I wish I still had mine, never should of sold her.

Yours also did not like being run when the boat was on the lift. :eek: :stooges:

LOL. What's this start button for? That's what friends are for, pushing stuff they shouldn't! :angry-smiley-038:

see if the exhaust wxits into one of the engines tail pipes..might be drowning the generator with water..

Could it be that the main engines are starving it of air under the hatch?

The Gen plumbing is dedicated only to the gen. The intake and exhaust is plumbed only for the gen and it has no ties at all to the engines.

The impeller cover gets warm which is a strong indicator it is a lack of water. Three 502's can pull some air but the vents for the engine bay pull air pretty well for everything under the hatch.

Well I got a reply from TAG today and the inability to run a gen on plane is common to the FASTech. The aeration of the step is too much for water to keep adequate flow and pressure for the strainer that supplies the gen.
I have a project it seems now. We require the gen to run on plane so moving the pickups for the gen and AC is what it will take for that part to work.
Pizzer that Fountain sets up their gens to run on plane but Formula does not.

I ran mine for 2.5 hours at 35 to 50 mph in 2-3 waives from St. Pete to Captiva Island over the holiday and the generator ran perfect. I don't think moving the water pickup will be that big of a deal. Teague Custom Marine even has a transom pick up that is adjustable to get the right amount of water to the intended target. Good luck.

Instead of moving the pickup try a larger sea strainer first. Maybe it will hold enough volume to compensate.