2019 255 Scarab overheating

[BartleySC]

Help. First trip out this season and both 250s are running between 230-240. Coolant was low in both reservoirs. Filled them up and still overheating. Only 70 hours on motors?

 

[Acard7]

Disclaimer: I know nothing about Scarab boats lol.

Thermostats already bad? How low is low in the reservoirs? Like just below the Low line? Or like had to had a gallon each?

 

[BartleySC]

Disclaimer: I know nothing about Scarab boats lol.

Thermostats already bad? How low is low in the reservoirs? Like just below the Low line? Or like had to had a gallon each?

I had to add a half gallon total to get both reservoirs to the full mark. Do 1/4 gallon to each. They didn’t drop at all after I ran the boat today. I only ran it like 10 minutes.

 

[BartleySC]

I had to add a half gallon total to get both reservoirs to the full mark. Do 1/4 gallon to each. They didn’t drop at all after I ran the boat today. I only ran it like 10 minutes.

It’s weird that both motors are doing it. This is my first jet boat so I feel like I’m missing something.

 

[Acard7]

Run in freshwater or salt? Not that it matters since yours is a closed cooling system. Just wondering if the salt air would ruin those temp sensors? Can’t imagine the sensors or thermostats are bad already but who knows.. Do you by chance have a warranty still?

 

[BartleySC]

Run in freshwater or salt? Not that it matters since yours is a closed cooling system. Just wondering if the salt air would ruin those temp sensors? Can’t imagine the sensors or thermostats are bad already but who knows.. Do you by chance have a warranty still?

No warranty, I run them in freshwater. Do you know how I would test the thermostats or sensors?

 

[Acard7]

No warranty, I run them in freshwater. Do you know how I would test the thermostats or sensors?

Sorry no idea how to do that.. Hopefully some scarab people will chime in soon. The only thing I would do is locating the thermostats, taking them out, and inspecting them..

 

[Luc Lafreniere]

First question, how old is your coolant? What type of coolant is it? Coolant does need to be the right type and of the right age. You can also buy a hydrometer (cheap) to test the coolant to see if it's still working as intended.

As you said, if both engines are doing, it's likely a common problem... very little is shared except the coolant itself.

Something else to consider are air bubbles in the system. Which could also explain low coolant as it burps the air out.

So who did the last coolant change? lol

@Acard7 unlike other brand loyal people, I welcome all ideas from everyone! lol

 

[BartleySC]

First question, how old is your coolant? What type of coolant is it? Coolant does need to be the right type and of the right age. You can also buy a hydrometer (cheap) to test the coolant to see if it's still working as intended.

As you said, if both engines are doing, it's likely a common problem... very little is shared except the coolant itself.

Something else to consider are air bubbles in the system. Which could also explain low coolant as it burps the air out.

So who did the last coolant change? lol

@Acard7 unlike other brand loyal people, I welcome all ideas from everyone! lol

I bought the boat 8 months ago. I’ve never changed the coolant. Do you recommend flushing coolant out then seeing if that makes a difference? If the cooling plate gets hot when running it does that mean the thermostat is working?

 

[Luc Lafreniere]

Since it's a 2019 boat and you don't know the history of the coolant, most definitely.

Very simple to replace. Get the right coolant from BRP (not the time to be cheap, it doesn't cost much more than generic stuff and since you're troubleshooting...)

Open the drain plug on the ride plate. Let it drain fully. You can open the reservoir let air in. Once fully drained, rinse it out with demineralized water. Then start topping it while you have a second person watch the flow at the other end. Once it's the right color, get that person to plug it again.

Then close the reservoir and run the engine for a few seconds. It may burp some air. Top accordingly. Not the reservoir markers are for when the coolant is cold not hot.

Careful when running the engine out of water. Follow proper procedure for this so you don't cause more damage.

 

[BartleySC]

Thanks so much. I’ll start with this

 

[SwissDoo]

Not quite clear, is this your first trip ever with the boat, or just for this season? So you can confirm the issue was not present last season?

Can you verify the temps, like with the exhaust temp vs engine temp? Are they really running hot, or just getting the signal from an invalid sensor input?

I would only water test btw, you don't want to cook those carbon rings!! You will not get the engines hot enough on the water hose befor toasting other parts.

If you think there could be air trapped in the cooling system, the quickest way is to remove the cap of the reservoir, block the overflow hose with your finger and blow in the reservoir.
Sounds like a joke, but it saved me once after a coolent hose poped off the water pump. Only way to purge the system if the boat is in the water.


Patrick

 

[BartleySC]

Not quite clear, is this your first trip ever with the boat, or just for this season? So you can confirm the issue was not present last season?

Can you verify the temps, like with the exhaust temp vs engine temp? Are they really running hot, or just getting the signal from an invalid sensor input?

I would only water test btw, you don't want to cook those carbon rings!! You will not get the engines hot enough on the water hose befor toasting other parts.

If you think there could be air trapped in the cooling system, the quickest way is to remove the cap of the reservoir, block the overflow hose with your finger and blow in the reservoir.
Sounds like a joke, but it saved me once after a coolent hose poped off the water pump. Only way to purge the system if the boat is in the water.


Patrick

Thank you for your advice. To answer your question I wasn’t having this problem last season. I live on the inter coastal here in Myrtle Beach so It’s easy for me to check the temps. I’ll make sure there’s no air in system then check the exhaust and engine temps with an infrared thermometer in the next couple days.

 

[SwissDoo]

So no work done to the boat, then both engines have a temp problem at season opening?

Can't you see the exhaust and engine temps on the display? Don't know when Scarab introduced this feature.

 

[BartleySC]

No work was done to boat. I even had a little engine heater that blew warm air anytime it got below 40 degrees which I now know I didn’t even need. Yes both motors are doing it. I believe the only time the engine temps pop up is when they go above 230. I was just saying I could check them with an infrared thermometer after running them for a few minutes on the water in the last response.

 

[BartleySC]

Since it's a 2019 boat and you don't know the history of the coolant, most definitely.

Very simple to replace. Get the right coolant from BRP (not the time to be cheap, it doesn't cost much more than generic stuff and since you're troubleshooting...)

Open the drain plug on the ride plate. Let it drain fully. You can open the reservoir let air in. Once fully drained, rinse it out with demineralized water. Then start topping it while you have a second person watch the flow at the other end. Once it's the right color, get that person to plug it again.

Then close the reservoir and run the engine for a few seconds. It may burp some air. Top accordingly. Not the reservoir markers are for when the coolant is cold not hot.

Careful when running the engine out of water. Follow proper procedure for this so you don't cause more damage.

Ran the motor, plates don’t get even warm. Flushed the coolant. I’m going to replace water pump and thermostat. Do you happen to have manual or know where I can get one

 

[Luc Lafreniere]

Ran the motor, plates don’t get even warm. Flushed the coolant. I’m going to replace water pump and thermostat. Do you happen to have manual or know where I can get one

Check pm