Best way to Operate these boats and cooling

[r3cc0s]

My boat has pretty much been fully refereshed... full long block, rebuilt pump with new impeller, changed all the hoses, new battery, new MPEM, new starter, replaced countless rectifiers and did the CDI as part of the replacement of the engine etc...

I followed break in procedures and rarely go over the the weight rating, but knowing my 657x motor was meant for a little Jet Ski, I would imagine that proper operating is required to make this motor last anywhere near as long (i.e. 140+ hours)

So if I take into consideration the boat weighs at least twice as much as the Jet ski of its time and I carry 400lbs of cargo with passangers... is there any proper precautions to take when operating?

I NEVER run the boat in the powerband for more than 10 mins at a time (varying the throttle) when planed and will turn on the bildge fan to provide additional cooling. IF I ever run long, its only to puts around the channel with friends at barely more than idle.

FAQ?
I've heard I need to cool the motor down for at least the same duration you run - I know this was the case during the break-in period

Oil - of course run the best you can, though ours don't even need Synthetic - I run Amsoil Interceptor or BRP XPS. I still use the auto-mix and have tuned it to run rich. I'd rather have a bit more rich and change plugs than the latter.

Make sure the cooling is good - I always can see the pisser pushing a steady stream which is good and I'll run it on the hose every 2-3 runs on the lake just in case.
*Though the Head of the motor and Exhaust are always just "warm" to the touch, the block itself is pretty warm... like I can't keep my hand on it for more than 3-4 second... is that Normal?

ALSO - when I just puts around above idle, is there any risk that there isn't enough cooling as not a ton of water would be pushing through?

Any other suggestions to get my long block running as long as possible? - At what compression do you guys recommend a top end rebuild? (i.e. compression below 140?)

 

[Spider4real]

I think you are overthinking this. Just go with the load limit in the operators manual and don't worry about the fact the motor was used in pwc.

I don't see any need to run the bilge blower while driving. Fresh air gets into the engine compartment when you are driving. If it didn't the engine would be starved of air and turn off. Running the blower is doing very little. IMO.

I never heard you need to cool the motor for the same time you run it. I've had my Challenger boat for 15 years and never had an issue with it overheating or needing to take any special precautions to cool it down when my day was over.

You should not mix brands of oil. They don't always play nice with each other. Pick one brand and stick with it. If you change brands you should remove the old and replace with new.

I've never touched the block of my engines. If the head is cool then you are fine. There is no cooling in block itself. Just the cylinders and head. So it is what it is. Just make sure the temperature sensor and your warning beeper are working.

I have spent many hours idling around in no wake zones and the engine gets the water it needs to keep cool. No worries there.

I personally have no experience when it comes to what psi you need to have for a rebuild. The one engine I rebuilt was at 0, so it was an easy decision. I have read on this site when you hit 135 it might be time to consider it. But I also have seen members that will let it drop to 125-130 before rebuilding. But 135 is probably the first milestone you will hit which is telling you the engine is getting near to the end of its service life and you can plan the next steps once there.

 

[r3cc0s]

I think you are overthinking this. Just go with the load limit in the operators manual and don't worry about the fact the motor was used in pwc.

I don't see any need to run the bilge blower while driving. Fresh air gets into the engine compartment when you are driving. If it didn't the engine would be starved of air and turn off. Running the blower is doing very little. IMO.

I never heard you need to cool the motor for the same time you run it. I've had my Challenger boat for 15 years and never had an issue with it overheating or needing to take any special precautions to cool it down when my day was over.

You should not mix brands of oil. They don't always play nice with each other. Pick one brand and stick with it. If you change brands you should remove the old and replace with new.

I've never touched the block of my engines. If the head is cool then you are fine. There is no cooling in block itself. Just the cylinders and head. So it is what it is. Just make sure the temperature sensor and your warning beeper are working.

I have spent many hours idling around in no wake zones and the engine gets the water it needs to keep cool. No worries there.

I personally have no experience when it comes to what psi you need to have for a rebuild. The one engine I rebuilt was at 0, so it was an easy decision. I have read on this site when you hit 135 it might be time to consider it. But I also have seen members that will let it drop to 125-130 before rebuilding. But 135 is probably the first milestone you will hit which is telling you the engine is getting near to the end of its service life and you can plan the next steps once there.

This is such an Amazing response @Spider4real - Thank you!

Blower:
You are probably right about the blower . Prior to the rebuild of my motor, I was running 135/130 and in order for the motor to get into the powerband and plane and stay there, I needed to give it more oxygen and Cooling or so I thought.

Since the rebuild, you likely are right - I don't need to run the blower other than to clear fumes.

Cooling:
I heard this from a couple people who run their PWC's hard... mostly all kitted with oversized pistons, MSD ignitions with higher rev limits and pipes. They usually run for like 10 minutes while chasing Boat wakes or near a channel coming into a lake, then rest it for another 10 minutes.

I DO notice that a "hot" engine that has been running hard for 10-15 minutes will need just a bit more throttle to use the powerband to get planing. @Spider4real do you think this is just normal?

The heads and pipes are definately cool to the touch... I confirmed the pump passages are clear and the pisser has a steady stream. As you stated, the Jugs are not cooled, so those are the only things that feel hot when I put my hands on it.

Also I am very happy to hear that even while idling along, the motor recieves adaquate cooling through the pump.

Oil:
I meant to say is that I am still using the auto injector and not manually mixing my fuel. I do believe my mechanic who rebuilt my carbs is running it a bit rich... but he did say that as the Oil Injection adjusts for throttle, its better to run rich as it will only do 40:1 at near WOT

I did MIX some BRP XPS2 (maybe a litre) with Aimsoil Interceptor after rebuild... my mechanic thinks as both are high quality the nature of the oils won't be too much of an issue. Since, I only run Amsoil Interceptor and have heard of people with 717 based PWCs (mine is 657x so similar) getting ridiculous hours.

Longevity:
"time will tell" - I think with a 2 stroke, hour meters don't translate quite the same way, and its all based on compression.
Like any motor, break-in and then general use will dictate longevity.

With fuel/equipment, kids and wife I basically am at that 650lbs GVW most of the time I'm riding, and once in a while I'll pull a single tube, which the boat definately notices.
I reckon with more load, the more fuel, the more wear...

I'll keep any eye on compression and let you guys know how it goes. I think if I drop below 140, I'll just do a top end kit and then sell her off

 

[Spider4real]

You cannot compare your stock engine to some highly modded engine. Just follow the owners manual for your regular stock motor. If every motor had to be used as you described nobody would be buying these things. Or they would be blowing up all over the place.

I had never noticed any difference in the performance of my engine once it has been warmed up or ridden hard. I cannot say for sure if what you are experiencing is normal or not. But a cold engine does seem to perform a bit different than a warm engine so by that logic if the engine was hot it may perform a bit different than a warm engine. As long as you get up on plan and the head is not super hot I would think everything I ok. If it gets too hot the boat will let you know. Assuming your temp sensor and beeper are working.

The jugs are cooled. They are surrounded by water jackets. When I say block I am only talking about the bottom which holds the crankshaft. I have never touched the side of the jugs either so I don't know how hot they get. If it does not burn your hand I would think it is ok. Engines get hot, this is normal.

Cheers

 

[POPPS]

Way over thought,,,unless you were at havasu racing for the world championship,

 

[r3cc0s]

ran it like I stole it. Probably never ran it more than 20 minutes at a time near weight capacity... but I do notice I need more "gas" to get it up to plane.

When the engine is cold-ish (say had 10 minutes cool down), it hits the powerband, what I feel is harder and requiring less throttle.

Not sure if this is a normal thing

 

[WhiteZombie]

The manual is pretty clear in stating to never run the exhaust fan while operating the engines. Seems the engine doesn't need to be competing with the fan for air that the fan is blowing out of the compartment. The exhaust fan can easily pull a couple inches water column of vacuum, and they aren't exactly allowing a lot of air in the air filter housings to begin with.
I know nothing of the high performance racing machines, but if they are running their fans while operating, I would think they are most likely blowing air in to pressurize the compartment to make air more readily available, not out of the compartment, which will create a vacuum for the engine to have to overcome to take in what should otherwise be effortlessly and readily available air.
What the OP describes on the engine head is what I experience and to me is desireable. Touching with hand for 4 to 5 seconds is about all you can do around 140- 150 degrees, which is rather cool to only be like 3/4" from the top of the cylinder itself.