HP500 stalls when getting on a plain
 

50 Hours on a new HP500 Carb - Ran fine last season and the first weekend we had it out this season. It has not been right since then. The problem appears to have started when I added roughly 40 Gallons of the 10% fuel, ran the boat up to around 3700 RPM's and it started acting as if it was starving for fuel. Couldn't get up on a plain again.

The Boat has been at a local reputable performance boat shop with no luck on repairs. They rebuilt the carb, changed plugs and sent me on my way. I ran the boat for 20 Minutes at all RPM's and the exact same thing happed.

Any help would be greatly appreciated....

Re: HP500 stalls when getting on a plain
 

drain water separator and see what the fuel looks like, you may have to drain/ change them several times......

the ethanol stripes all the varnish off the inside of your tank.....if you have a fiberglass tank it will be much much worse

Re: HP500 stalls when getting on a plain
 

Thanks for the response. I've changed the Fuel Separator several times but don't really see any water. Is it possible that water in the tank is mixing with the 10% fuel and slipping by the separator due to the new charachteristics of the Ethanol?

I could go start the boat today and it would run fine until I hit a few wakes or shake it around trying to get on a plane.

Re: HP500 stalls when getting on a plain
 

As I've mentioned in a couple other threads, I chased the same damn problem for over a year. Turns out I had a weak fuel pump. :(

Re: HP500 stalls when getting on a plain
 

Thanks for your help. Was it able to run fine some times and then fail? Mine drops off and leaves me getting home at 1000 PPMs or less running very rough. The next day, I can rev the motor and maybe get it over 4000 rpms for a few minutes before it fails.

I'll change the fuel pump tomorrow but it seems to be tied to motion. Does that make sense? The motor has less than 50 Hours on it?

Thanks again!

Re: HP500 stalls when getting on a plain
 

When that happened to me I had water in the fuel and when I tried to get on plane the water bubble (resting on the bottom of the tank) ran up to the pickups and killed the boat. Then I would start it again and it wouldn't die until I went bow up to get on plane. I took off the sending unit (carefully and well planned) and looked into the tank and saw my bubble.

I pumped it out with a plastic hand pump on a cool windy day.

A gas dryer will disperse it so it will make it through your system, but doesn't actually eliminate it.

Re: HP500 stalls when getting on a plain
 

That sounds exactly like what I'm seeing. I actually took it for a spin today after the shop rebuilt the carb and having a new distributor cap and rotor kit installed. Purrs like it should at idle, got it up on a plane and it seemed like it ran out of gas. Went back to idle and it was fine. Tried to get it back up and the same thing happened. I'll be draining the tank tomorrow if this rain ever stops.

Thanks for everyones help...

Re: HP500 stalls when getting on a plain
 

Did you change the fuel pump?

Re: HP500 stalls when getting on a plain
 

I was told by the machanic at APM that they checked the fuel pressure through the RPM range and found it to be OK. It's the machanical fuel pump attached to the waterpump. If the changing the fuel doesn't fix it, that's my next move.

Thanks again for the help.

Re: HP500 stalls when getting on a plain
 

I'm also betting on water in the fuel. Had almost the same thing happen. The only thing strange is that it will idle fine after it starts to bog out after trying to get on plane. I had to dump my fuel/h20 separator about 4 times before all the water was finally gone.

Dump the fuel/h2o sep filter into a clear glass and let it set for a while. See if you can see a separtion. Fuel is lighter and will be on top.