Limiting hours

[MvM]

So, I’ve been killing the engine when not running. Always have it off when sitting still for any reason. I assume the hour meter only runs when the engine is running, not when tige touch powers on? Would you be concerned at all about the contact starting and stopping of the engine? Is what I’m doing a good idea/bad idea?
Thanks!


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[JohnnieMo]

I don’t think stops and starts will be all that bad. Obviously leaving it running is not bad either (despite the hour number going up). I’ve always felt boats should be like farm equipment and take the engine “load” into account when reporting hours.

One thing to consider is if you are running at load and then stop suddenly (like to pick up a rider) you don’t want to kill a hot engine. Let it run a few minutes to cool the engine down. I’d be curious to hear other opinions on this.

[bsreid]

I try and kill it whenever we are idling, unless engine is warming up no point just leading them add up. If you don’t care about hour meters I’d just go FAE and idle but keeping hours somewhat low definitely helps.

[Bakes5]

Yeah...I turn mine off every time we do transfers. If it's a 10 second swap with nothing but experienced adults then I will keep it running. I absolutely hate it when someone keeps their boat running and you are doing things on the back of the boat like messing with bindings, talking, etc. We often have a bunch of kids so it adds an extra layer of security.

So explain to me why it's bad to be cruising, idle back to a fallen rider, swing the back of the boat around and then kill the motor. I'm not sure I understand the dont kill a hot motor concept. It's not like it 220 degrees running and then 160 degrees idling. I certainly don't wait a few minutes in the garage at home for my boat to cool off. I've heard your suppose to do that with turbos but my boats never had a turbo.

[MvM]

Yeah...I turn mine off every time we do transfers. If it's a 10 second swap with nothing but experienced adults then I will keep it running. I absolutely hate it when someone keeps their boat running and you are doing things on the back of the boat like messing with bindings, talking, etc. We often have a bunch of kids so it adds an extra layer of security.

So explain to me why it's bad to be cruising, idle back to a fallen rider, swing the back of the boat around and then kill the motor. I'm not sure I understand the dont kill a hot motor concept. It's not like it 220 degrees running and then 160 degrees idling. I certainly don't wait a few minutes in the garage at home for my boat to cool off. I've heard your suppose to do that with turbos but my boats never had a turbo.

Fear of vapor lock, maybe?


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[cltTige]

I would watch your hour meter as far as when it runs, I believe my last boat it ran whenever the key was in on position (which doesn't seem like it should be to me). Letting it idle is not what is going to make it fail early. Also, unless you got one of these new starting systems like in newer cars that cut off when at a stop light, you will probably burn more fuel starting and stopping than just leaving it running. I would argue about the life of the starter constantly starting and stopping (a big argument to the new cars for me too since we haven't really seem the long term impacts yet) but we shouldn't see wear and tear on the motor itself. Killing the motor and limiting hours will keep your resale value higher. So really its whatever you want more.

I leave mine running when switching riders, only kill it when people want to jump in or we anchor down.

[KoolAid]

Just depends the year model. Early units that had a rolling number gauge will keep going when key is on. In those cases, use Diacom to pull the actual engine hours off the ECM before selling.

I personally prefer to kill the engine every time I stop. I don't like the fumes at the back of the boat and the perception of hours when re-selling makes me want to reduce hours.

In all actuality, going into diacom will tell you exactly what rpm range the engines hours are. So when you buy a used boat with high hours, have them pull up a report on diacom. Maybe half of those hours are at idle and the other half is with a load. Just a way of getting a better understanding of how the engine was used.

[UNSTUCK]

I try and kill it whenever we are idling, unless engine is warming up no point just leading them add up. If you don’t care about hour meters I’d just go FAE and idle but keeping hours somewhat low definitely helps.

Don't think that because you have a fresh air exhaust that you can play around at the back of the boat with the engine running and be safe. FAE is only effective while underway.

[freeheel4life]

^^Koolaid nails it. I had an 16 RZ4 in a little while back and was surprised to see 311 hours on the clock. Had to hookup Diacom anyways so went to the RPM breakdown and found that 170 of the 311 was idle time.

[boatwakes]

I always find it funny how people think low hours mean good things for boats. Whenever we do a survey on a vessel and engine hours are less than 50 per year I will let the customer know they're going to deal with several mechanical issues. If you use your boat and it has problems then you deal with those problems as they happen. If you have low hours it means you don't use your boat and wear items have not been addressed.

I don't think that was the point of this thread but c'mon guys, use your heads. 80% of engine wear occurs at startup because theres no immediate oil pressure. Every time you start the boat you put stress on the start solenoid, flywheel ring gear, starter motor and nose gear. Engines stop in the same spot within a 20* arc every time they shut down and the flywheel ring gear wears in that same spot as a result.

Obviously you do you dude and none of us like exhaust at the swim step when we're getting ready but I would advise against stopping and starting multiple times to keep the engine hours down.

[cltTige]

80% of engine wear occurs at startup because theres no immediate oil pressure. Every time you start the boat you put stress on the start solenoid, flywheel ring gear, starter motor and nose gear. Engines stop in the same spot within a 20* arc every time they shut down and the flywheel ring gear wears in that same spot as a result.

I would agree with that 80% figure if you put cold in front of startup. If the engine is still warm the wear will be significantly reduced.

But yes, you are putting a lot more stress on the other components you talked about, but in the end, is it worth it if you can get 2k more out of your boat, and only replace the starter once? and flywheel ring gear I doubt you really have to worry about that having that must excessive wear. Also the same spot +/-20°? I have never heard of that. Not saying you are wrong, but I would say they stop whenever friction and compression over takes engine motion. Typically as a piston is approaching TDC. So is the spot 100% random, no, but it has multiple spots along the flywheel ring it will stop, each time with a different degree of uncertainty.

[sandm]

I turned off every time there was an extended rider swap, maybe more than a couple minutes. otherwise I left it running. my grandpa told me many many years ago that if you can shut an engine off and count to 20, you are saving gas but with today's injections sytems, I would bet that is not a true number anymore.
I never worried about co2 at idle as most times the boat was listed and exhaust was underwater. I figured the water did a pretty good job diluting the gasses and 10 years of boating never had anyone lightheaded from taking a minute on the transom to pee or put bindings on. did always try to play by the rules that if someone is in the water on the transom and engine was running no one was seated at the helm and I never had kids on the boat so not much worry about someone putting in gear.

[gumby]

Boatwakes is correct on the 20*+/- I could go into how it works but it would be boring and a lot for me to type. I leave mine running until we anchor up and let it idle for 2 to 3 min before shutting down just to help cool things down. Surfing works the engine pretty hard If you think about it 10=12 mph 3000-4500 RPM not a lot of air moving because of speed and the nature of the closed up box location. Water is the only source of cooling although it is somewhat good at removing heat it dose take time. Remember most if us are not running closed pressurized systems. So time at idle is a good thing just to cool things down. Remember we just don't cool the engine with water we cool V drive and transmission also and you don't have temp gauges on them. That oil gets a lot hotter than your 165-170 engine temp (like 2X more) IMO it is good to give them time to cool down.

[IDBoating]

80% of engine wear occurs at startup because theres no immediate oil pressure.

Bingo. Startup is the worst friction case for exactly that reason.

But everything is a tradeoff. It's also not good to idle an engine for excessive periods - even a four stroke engine. The key is to find a reasonable balance. If you're only stopping for a minute or two and there's little risk of exhaust gases causing trouble for passengers, leave the engine running. If you're stopping for longer than that, consider killing the engine. Just give it a little thought and do your best to make an informed decision each time. Simple as that.

As for running the engine to cool it off... it is true that the engine temperature can actually RISE when first turned off. The latent heat in the engine is still there, but turning it off instantly eliminates active water cooling. The "hot spots" in the engine then work their way to the outside surfaces of the block and then to the ambient air, so some sections of the engine will actually experience a rise in temperature since the water jacket is no longer sinking the heat away. Not really a big deal, but one thing I do is open the engine hatch when I've pulled into the dock (or onto the trailer) to replace the ambient air in the engine compartment with fresh, cooler air. There's usually several minutes of dock line management, or trailer strapping, or something and during that time you're letting the engine compartment dump a LOT of waste heat. If you're trailering, don't forget to close the lid before driving away!

Edit: Lack of oil at startup is also why I personally only use true liquid dinosaurs (my favorite for diesels and wakeboat engines is Rotella T4) and not synthetic engine oils... synthetics really are "slipperier", but a side effect is that they tend to run off of rings and pistons when the engine is stopped for a while, leaving them even DRIER than traditional oil. Synthetics in daily-use engines are fine (cars, etc.) but I only use traditional oils in anything that is occasional use (boats, jet skis, ATV's, loader-backhoes, snowblowers, lawn mowers, etc.). Using BoatWakes' number: If 80% of the wear occurs at startup, and an occasional use engine sits between uses for long periods, the oil is going to have a good long time to slink off all those expensive polished surfaces. Better to give those surfaces every advantage you can!

[cltTige]

I'm very interested in this singular +/- 20º spot and how that works. In my brain I see it stopping on any one of the 8 cylinders' compression cycle. But maybe thats a discussion for another time. If that is true, I did not notice extra wear in one spot on my flywheel when I replaced the engine.

Startup friction is only its worst at a cold start. If the engine is still warm when you recrank, the wear is significantly reduced b/c oil will likely still be covering the engine, and the oil is still warm therefore, it will not take but a short time for the pressure to build back up (talking like milliseconds).

All this being said, I agree with leaving the engine running, its easier, and its better for cooling. Just like ID said, the engine can heat up when you cut it off, and letting it idle for a minute is the better way to cool your engine, tranny, and v-drive to operating levels.

I agree with ID on using T4 oil for your engine. Works great and fairly inexpensive.