increase cooling?

[cybuch]

BTW, thank you all for the input!! This site is the best and this community rocks!! I appreciate all the help!

 

[bucks448]

Not to derail this thread, but @cybuch do you have another thread on the dual impeller setup? Any changes/improvement when using the boat normally?

 

[cybuch]

Not to derail this thread, but @cybuch do you have another thread on the dual impeller setup? Any changes/improvement when using the boat normally?

https://jetboaters.net/threads/dual-impellers-are-in.1853/#post-30277

 

[txav8r]

I had forgotten about the new impellers you installed. They were specifically designed to give good water pressure to your flyboard, and to increase flow through the cooling system? If your getting good pressure at the pee holes, and good flow out the exhaust, you must have sufficient water flow for cooling...may be back to the idea of ventilation. One of the two if it wasn't just a blockage as ya'll are considering.

 

[txav8r]

Hmmm, thats a thought. I did install dual impellers to combat that issue. Before the dual impellers, the boat would have cavitation, and no cooling issues. This was our second outing with the new impellers and first time for overheat.

If you were getting cavitation with the old impellers, it would stand to reason that if you maintained the high rpm's with cavitation, you would indeed end up with cooling issues. Because you lose laminar flow across the intake screen when the pump is cavitating. I just think this is a learning curve @cybuch you will get it dialed in. Even a helicopter has limitations as to how long it will hover without overheating. You may have limitations as to length of time at high power or high resistance on the engine. When the boat is running normally at high rpm, eventually, it is on step, lower resistance, with excellent water flow and ventilation.

 

[Julian]

I wonder if the engines alarm for more than just overheat? Do you have a YDS / YDIS cable and SW you can hook up? Perhaps it was just an intake temp issue? Would be good to get the code before you go too far.

 

[cybuch]

If you were getting cavitation with the old impellers, it would stand to reason that if you maintained the high rpm's with cavitation, you would indeed end up with cooling issues. Because you lose laminar flow across the intake screen when the pump is cavitating. I just think this is a learning curve @cybuch you will get it dialed in. Even a helicopter has limitations as to how long it will hover without overheating. You may have limitations as to length of time at high power or high resistance on the engine. When the boat is running normally at high rpm, eventually, it is on step, lower resistance, with excellent water flow and ventilation.

Great point!!!

 

[cybuch]

I wonder if the engines alarm for more than just overheat? Do you have a YDS / YDIS cable and SW you can hook up? Perhaps it was just an intake temp issue? Would be good to get the code before you go too far.

I do have it. I will check today and post my findings.

 

[cybuch]

Ok, pulled out the YDS and found some interesting stuff. I just had that motor rebuilt. Here is what it is reporting: 22 total hours, overheat at 9.22 hours. That's completely off. We didn't go for 13 more hours after the overheat.

 

[cybuch]

Well, had another over temp this past weekend. I am driving that engine hard for a long time and I am sure thats what it is. When I fly my GF, who is much lighter than me, no issues (7k rpms). But when I fly at WOT (9500 rpms), it will over heat after 40 minutes. I called Glenn at Skat-Trak and they are going to rep itch my dual impellers so I only have to go to half throttle, that should help with the cooling issue.

Here is a video of my GF having a go:

 

[Murf'n'surf]

Have you tried having the bilge fan on during high rpm run?

 

[cybuch]

Yes, running the fan the whole time. I am getting about 15 feet of height and I want some more so they are going to pitch the main to 7/14 and that should give me height with lower rpms. Saves fuel too!

 

[Murf'n'surf]

Maybe they could make an adapter that attaches to both pumps. That way you can run at far less RPM's but adds the problem of having the ability to move the boat.

 

[Gym]

Well, had another over temp this past weekend. I am driving that engine hard for a long time and I am sure thats what it is. When I fly my GF, who is much lighter than me, no issues (7k rpms). But when I fly at WOT (9500 rpms), it will over heat after 40 minutes. I called Glenn at Skat-Trak and they are going to rep itch my dual impellers so I only have to go to half throttle, that should help with the cooling issue.

Here is a video of my GF having a go:

Wow, she has that thing nailed. She looks very comfortable up there.

 

[Bruce]

I am surprised that you run it for 40 minutes. I believe that many "flying jet" rentals offer shorter durations.

 

[Gym]

Yes, running the fan the whole time. I am getting about 15 feet of height and I want some more so they are going to pitch the main to 7/14 and that should give me height with lower rpms. Saves fuel too!

With regards to the fan...Have you directed the fan duct onto the engine? Just cut the tie wrap to redirect the fan hose. The bilge fan is normally down low in the engine compartment to vacate any gas fumes so would not blow directly on the engine.

 

[cybuch]

Maybe they could make an adapter that attaches to both pumps. That way you can run at far less RPM's but adds the problem of having the ability to move the boat.

I don't want to lose the ability to move the boat when needed.

 

[cybuch]

@Gym Haven't tried to move the vent hose, will give that a go next time. Impeller won't be back time next week, good thing I have 2 sets.

@Bruce I run it for 40 minutes for me. Most our renters are 15 to 30 minutes and not WOT.

 

[cybuch]

Wow, she has that thing nailed. She looks very comfortable up there.

Yes she is! She wants to go higher now. I told her she's ready for back flips....lol

 

[Murf'n'surf]

Do you alternate flying on the motors?