New project boat -1986 Ski Nautique

[Zeke]

Yes, boats that use the water they are floating in for coolant should have a t-stat. I agree that some of the water is not ideal but the intake is not at the surface. There would be a screen. Still, running in nasty water can't be good and some boaters probably need to check the inlet if the temp gauge goes up.. I've seen a fish in a pump, not pretty.

[TimT]

Engines cooled by raw salt water are rare.. I've had boats I operated in salt water, on and off for the past 40 years or so, other than outboards which are salt water cooled..

Inboards have a close cooling system with a fresh/salt water heat exchanger, the salt water is picked up from a through hull scupper via pump, passed through a heat exchanger, and dumped into the exhaust and out of the boat..

Many of the outboards I've owned had a hose bib where you could flush the cooling system after use..

I'm lucky in the the canal across from my house is partially fed by a chain of fresh water lakes.. So when I return to dock I just let the engines run a few minutes and flush with the brackish water.. I also changed the impellers yearly during the off season..

Typicall cooling system for a boat operated in salt water..

[JeremyD]

Originally Posted by onewhippedpuppy

For cooling, most boats have a raw water pump that sucks lake water out of the lake, which then feeds the engine cooling system water pump just like a car would have. After the lake water is circulated through the engine it dumps overboard. So basically the lake is your radiator. But as you expected this gets really corrosive in salt water, most boats have a hose connection so you can flush out the salt water with fresh water when you’re done. There are also boats that have a closed cooling system and radiator like a car, but they aren’t as common.

I have two 5.9 Cummins that have Heat Exchangers for the motor, gear cooler and a raw water cooled intercooler (called an aftercooler on the boat version) Even with a closed cooling system - it still would get pretty salt encrusted - so I installed a fresh water flush for the raw water side. The engine side is cooled with coolant.

Several challenges with this - #1 you have to replace your zincs on a consistent basis or they with galvanic corrode and suck your coolant (or in the case of the gear cooler, gear oil) out the exhaust - or clog up the aftercooler - and you can't make boost.

Nice work Tim - a steal on the boat - probably the trailer alone is worth more than that.

[Tim Hancock]

Got the transmission put back in and realigned the engine to the shaft. This morning I did a quickie buff job on the boat and cleaned then re-installed the interior. took it out this afternoon for a test run. Daughter and SIL were out on their GS24 so my daughter hopped in our boat to christen our Nautique by skiing behind it.

Boat ran great. Still need to diagnose why tach, temp gauge and one of the speedos does not work. I don't think my wife likes this "little" simple boat as much as our bigger boat but no matter what, this was a great buy.

[juanbenae]

Originally Posted by speeder

My powerboat knowledge is weak, so here's a dumb question I've always been meaning to ask someone; does the inboard engine just use unfiltered lake water to cool it and do they use the velocity of the boat to force it through or do they still have a water pump like an automotive arrangement? I guess they would have to in order to cool when standing still(?)


Sorry for the highjack but I figure this thread is the place to get answers. Very cool boat, Ski Nautique was just the gold standard back in the day. Maybe still is? Does it have the big roll bar deal with the tow line attached to the top of it so the skier can get alongside the boat?

I too just got the same year Nautique and have been doing work on it, although nothing extensive as Tim has going on... And I don't fly to pick parts up...

One of the 1st things I did was replace the water intake impeller on mine as they are a wear item and should be replaced every few years. Here is a photo of mine with the cover off and old impeller in place. It pulls water from an intake at the bottom of the hull then pushes water into the motor where a standard automotive type water pump then takes it and circulates it throughout the motor, tranny cooler and an canister oilcooler that is mounted just off the motor. You can see it just below the impeller housing, which being apart does not show the pully that is belt drven off the motor.

Originally Posted by Zeke

Yes, boats that use the water they are floating in for coolant should have a t-stat. I agree that some of the water is not ideal but the intake is not at the surface. There would be a screen. Still, running in nasty water can't be good and some boaters probably need to check the inlet if the temp gauge goes up.. I've seen a fish in a pump, not pretty.

Another bit of coincidence here is I was not seeing my temp gauge move at all in the 1st outing so I replaced the sender. Got a bit more temp in it yesterday, but nothing greater that 110* and from what I've read and Milt alludes too you actually need have a bit more temp for motor health. When I got the sender I went ahead and ordered a 140* thermostat as well and got to installing it today. Well, I found my over cooling issue was there was no thermostat in place!! Went ahead and cleaned up the housing and the intake the housing mounts to before the motor. Painted and will reassemble tomorrow.

There is a strainer all the water flows through just before the transmission cooling inlet that can be screwed off and the screen cleaned. Infact Tim shows it in one of his early photos in this thread, the see through canister in his shot of the back of the motor.

Not to highjack, but is relevant to the topic and my current efforts.

[juanbenae]

One other thing, the current craze of wake board and wake surfing requires a hug wake to be effective. The tourney boats were designed to do the opposite in making very little wake for slalom skiing.

Great shot Time shows of how cool, IMO these boats look in the water, so low, like a sports car...

[Tim Hancock]

My temp gauge starts an 100... It might of hit 105 so I figured it was not working. Maybe my thermostat is missing too.

[juanbenae]

Originally Posted by Tim Hancock

My temp gauge starts an 100... It might of hit 105 so I figured it was not working. Maybe my thermostat is missing too.

Thought it was the gauge initially after reading on a couple forms that they can get pretty beat with all the jarring a boat presents. Found you can test the gauge by grounding the sender to the block and if it pegs the gauge and wiring is sound. They suggest a quick grounding as it applied to ground for too long it can mess the gauge up.

My next task is to adjust the gear engagement cable. Mine will rev a tad too much before forward or reverse is engaged. Hoping adjusting at the motor does it cause getting into the shifter case at the driver seat seems like a can of worms.

The other thing that has concerned me is the janky, nearly 40 y/o push button accessory buttons. One of mine, the auto bilge button is broken, I have already replaced the ignition button with a toggle switch as to not get stranded if that one decided to quit on the water.

[Tim Hancock]

Originally Posted by juanbenae

The other thing that has concerned me is the janky, nearly 40 y/o push button accessory buttons. One of mine, the auto bilge button is broken, I have already replaced the ignition button with a toggle switch as to not get stranded if that one decided to quit on the water.

Crazy ..... My auto bilge button was stuck in the on position also. Rest of buttons worked good. I sprayed wd40 around button several times and now it is working properly again.

[speeder]

WD-40 is such a miracle drug in so many situations. Light solvent/lubricant/cleaning solvent...when I hear or read someone say that it only disperses water, I know that I'm dealing with an idiot.

[Scott Douglas]

Hey Tim,
You haven't mentioned anything about looking at the trailer wheel bearings, tires etc.
How are you approaching that?
Dad ingrained me with a lot of angst about wheel bearings but it was based on his experience up in Alaska and now I fully understand where he was coming from. At the time he had us repack the trailer wheel bearings before every vacation, I didn't grasp his need to have them done.

[speeder]

Originally Posted by Scott Douglas

Hey Tim,
You haven't mentioned anything about looking at the trailer wheel bearings, tires etc.
How are you approaching that?
Dad ingrained me with a lot of angst about wheel bearings but it was based on his experience up in Alaska and now I fully understand where he was coming from. At the time he had us repack the trailer wheel bearings before every vacation, I didn't grasp his need to have them done.

Your dad was smarter than the average bear, or maybe he just had a dry trailer bearing turn into molten lava once and shear off the trailer wheel. No wait, that was me.

[Tim Hancock]

Trailer spent whole life at Lake where I bought boat. Only used to put in and take out boat seasonally. About 1/2 mile each way at 25 mph max.

That said, the chrome original wheels are rusty and the possibly original whitewall tires are dry rotted. I will get new tires next spring. The axles have bearing buddies and I have not touched them yet. I plan to repaint the trailer eventually and I will completely go thru it.

[Scott Douglas]

You're a braver man than I, Tim.
I never would have let my wife tow the boat home without having first looked into the condition of the tires and the bearings.
I've seen the results of too many blown tires that ruined a nice vacation. Risking that boat with those tires would not happen on my watch.

My Dad was on a family vacation back in '48. Grandpa had taken his entire family on a road trip to Alaska. One of the cars was pulling a 1/4 ton ammo carrier trailer and the wheel bearing went out, in the middle of nowhere on the Alcan Highway.

Dad said he'd take care of it and left to go to a Quonset hut he'd seen a couple miles back that was at an old airfield. The Alcan was built by the Army and they put in airfields every couple of hundred miles for flying in supplies.

He got to the hut and the Sgt there said he could have anything he needed if he could find it. Dad had been a quartermaster in the Navy so knew enough about how things were stored so was able to hunt down the exact bearing he needed.

When he got back to Grandpa and the gang and pulled out the correct bearing for the wheel, I think it was then that Grandpa knew Mom was making the right choice. I don't believe they were married at the time, or had just been married. Anyway, Grandpa almost fell over in disbelief at what Dad had found, literally out in the middle of nowhere.

And that is why my brother and I got really good at packing wheel bearings at an early age. Our Boles Aero trailer was tandem axle so we got lots of practice.

[Tim Hancock]

We had a spare tire with us. If not I would have been more nervous. I followed behind her the whole way.

[Dan J]

I think second guessing Tim on tires and wheel bearings is a fools errand
He's a more then proven "Big Boy" and his decisions as to using this equipment should be taken as
more then competent

[1990C4S]

A broke down trailer is really just an opportunity to fly somewhere to grab parts.

I think if he's doing low speed stuff and short distance he's fine. But checking bearing temps with a laser temperature sensor after a drive is pretty easy and a good way to look for a failing bearing.

[Tim Hancock]

Originally Posted by 1990C4S

A broke down trailer is really just an opportunity to fly somewhere to grab parts.

I think if he's doing low speed stuff and short distance he's fine. But checking bearing temps with a laser temperature sensor after a drive is pretty easy and a good way to look for a failing bearing.

I actually had a laser temp sensor with me and have used it when pulling heavy max loads on my trailers long distances to check my bearing temps ay gas stops. I was not worried on this trip home as the trailer's bearing buddies had grease showing on them. It just had to make it home... and it did...

I have owned, restored, built and used many trailers over the years. I get the point being made about bearings and tires, but it was not an issue for me.

[Scott Douglas]

Originally Posted by Dan J

I think second guessing Tim on tires and wheel bearings is a fools errand
He's a more THAN proven "Big Boy" and his decisions as to using this equipment should be taken as
more THAN competent

Fixed it for you Dan J.

I wasn't questioning his "Big Boy" abilities so much as his story telling ones.
No where does he state how far he had to drive home.
No where does he state he even looked at the bearings or tires for that matter.
We can only surmise, from his pictures, that he inspected them to the point of verifying they held air, as they appear to be inflated.
I was just hoping those things had been looked at to avoid this great purchase ending up a wreck from a blown tire on the freeway or something like that.

[Zeke]

Originally Posted by Tim Hancock

Crazy ..... My auto bilge button was stuck in the on position also. Rest of buttons worked good. I sprayed wd40 around button several times and now it is working properly again.

Originally Posted by speeder

WD-40 is such a miracle drug in so many situations. Light solvent/lubricant/cleaning solvent...when I hear or read someone say that it only disperses water, I know that I'm dealing with an idiot.

In the world of antique radio repair there is the perpetual debate about WD vs. contact cleaner and a product called Deoxit.

WD seems to work fine for those that believe, and is not good for the non believers.

Typical of everything.