Rotax 4Tec 200 overheating

[Ralph195]

I have a 2016 Scarab 195 with a Rotax 4Tec 200 with cat.
I keep on overheating.
Flushed the closed loop coolant per service manual.
Flushed the engine though the flush port about 7 times.
Put the boat back on the water after 15 minutes the temp started rising from 192 to 219 and after 15 min to 230....overheating.
No obstruction in the crate....
First question....does anyone know the normal operating temp?
Second question.....does anyone know what could be causing the overheating after everything I have done?
Frustrated......
Thanks for any input

 

[Rick215HO]

Normal op temp is under 200F.
Is the ride plate warm? If its not warm you may have an obstruction, air in the system, or a faulty thermostat valve or coolant pump impeller.

The thermostat opens at 188F. Thermostat is inside the pump housing and the pump housing is in the back of the engine, this is some work.

The manual tells you to check the hose going into the pump, it should be hot above 188F, probably hard to check in our boats (this is why I suggested to check ride plate temp.)

 

[Ralph195]

Thanks Rick for all your information....very helpful.
I did check the hose coming out of the pump and it was a little warm at start then I checked it later at 190 and it was hot....so I think the thermostat is opening. I fear that it was the thermostat and like you said is a very big job to get to that thermostat.
I'll check the ride plate as you suggested tomorrow.
If there's air in the system is there a way to bleeding like you do in a car brake?
Thanks again Rick

 

[Rick215HO]

There doesn't seem to be a way to bleed it, it seems that eliminating air pockets is all depending on how you fill it (level, and let some coolant flow through before you close the plug on the ride plate) On some engines I use a vacuum filler but I couldn't even figure out how to do that here. Hopefully some of the real experts on this site respond.

Did the problem start after a coolant change or any other work on the boat? or did it start on its own?

 

[Ralph195]

Thanks Rick for all your help
Thinking back it may all have started when my factory filled coolant level was low and I added the recommended coolant that is in the manual that is an orange color...the coolant that came from factory was a green color but I did not pay too much attention to this color difference, I figure that the factory coolant and the manual recommended one will be one of the same. At this moment I found out that the mix will cause problems.....BRP should use the same coolant at the factory as the one in the manual. If there is a Moderator of this forum reading this hopefully he or she would chime in.
Thanks Rick....stay safe.

 

[WREKS]

@Ralph195 I am not familiar with the cooling systems for theses engines, but you said you have a closed loop coolant system and a system to flush the engine. Is it possible there is blockage in a water-jacket. Have you used an ir thermometer to try identify a hot spot?

 

[Bud195HO]

@Ralph195 Did you find out what the problem was? I have a 2017 195 Open and is doing the same thing. I can run about 6600-6800 rpms and keep the temp just above 200. But if I get around 7000 it creeps up to around 215 in about 3 minutes and WOT will overheat in 4 minutes. It has been in and out of the shop several times and no fix yet. Mechanic ordered a new ride plate but is not sure if that is the problem.

 

[Dean P]

@Ralph195 Did you find out what the problem was? I have a 2017 195 Open and is doing the same thing. I can run about 6600-6800 rpms and keep the temp just above 200. But if I get around 7000 it creeps up to around 215 in about 3 minutes and WOT will overheat in 4 minutes. It has been in and out of the shop several times and no fix yet. Mechanic ordered a new ride plate but is not sure if that is the problem.

It's worth a shot as these are truly the only option the engine(s) have to cool.

 

[ALAN MANN SR.]

Check the cap on the over flow tank. If it is loose the engine will heat up fast a hi RPMs. Had that happen to me and had it to dealer, and they said nothing was wrong. Tighten the cap and it was fixed.

 

[Bud195HO]

Thanks. I will double check the cap the next trip out.

 

[Scarabpaul]

why don't you flush the coolant? its a simple process. the drain bolt is at the back of the boat on the ride plate. a cheap option and its sounds like you mixed coolants anyway.... YouTube has a simple video, I believe you need 2 people....

 

[Bud195HO]

It is still under warranty and the dealer already flushed it or supposedly flushed the system. The coolant level has always been good and if it was mixed then the dealer mixed it as I have never had to add any coolant. They are leaning towards the ride plate being partially plugged by something.

 

[Luc Lafreniere]

@Bud195HO Nobody painted the ride plate right (you or a previous owner)? Just checking since you're running out of reasons why this is happening. lol

 

[Bud195HO]

Luc, I saw that mentioned in a different thread but I am the only owner and it has not been painted that I can tell. I have just over 100 hours on the boat and this just started in the beginning of September. I have not had any issues till now.

 

[Ralph195]

@Ralph195 Did you find out what the problem was? I have a 2017 195 Open and is doing the same thing. I can run about 6600-6800 rpms and keep the temp just above 200. But if I get around 7000 it creeps up to around 215 in about 3 minutes and WOT will overheat in 4 minutes. It has been in and out of the shop several times and no fix yet. Mechanic ordered a new ride plate but is not sure if that is the problem.

Sorry I replied so late just saw your question.
Here is what was found Amongst other things but I will start with.
If you're not losing coolant I will start with the vent hose that goes to the top of the coolant tank it was collapse inside and clogged, in the outside it looked fine.
If you are losing coolant have the tank pressurize because mines had a hose that was cracked and would only lose coolant at high rpm when the crack opened up and coolant leaked.

 

[gjj1212]

@Ralph195 Did you find out what the problem was? I have a 2017 195 Open and is doing the same thing. I can run about 6600-6800 rpms and keep the temp just above 200. But if I get around 7000 it creeps up to around 215 in about 3 minutes and WOT will overheat in 4 minutes. It has been in and out of the shop several times and no fix yet. Mechanic ordered a new ride plate but is not sure if that is the problem.

I also have a 2018 195 Open running the same issues, seems to be getting up to 204 degrees, Ralph195 did you ever get a solution or answer for yours?

 

[Luc Lafreniere]

@gjj1212 204 isn't way out of wack and shouldn't be triggering a light. But when was the last time the coolant was changed? Is it topped up properly? (between min/max on the reservoir when engine is cold)

 

[MD23679]

I also have a 2018 195 Open running the same issues, seems to be getting up to 204 degrees, Ralph195 did you ever get a solution or answer for yours?

Check the water pump / thermostate ...

I have a 2016 Scarab 195 with a Rotax 4Tec 200 with cat.
I keep on overheating.
Flushed the closed loop coolant per service manual.
Flushed the engine though the flush port about 7 times.
Put the boat back on the water after 15 minutes the temp started rising from 192 to 219 and after 15 min to 230....overheating.
No obstruction in the crate....
First question....does anyone know the normal operating temp?
Second question.....does anyone know what could be causing the overheating after everything I have done?
Frustrated......
Thanks for any input

Check/replace the water pump housing and thermostat ... I had the same issue at 120hrs and all is good now .
I have a twin 250hp closed loop coolant system. It overheats after 6500 RPM

 

[Ekun]

I have the same issue with my 2016 Scarab 165 Ghost. To be frank, I didn't even realize the boat was overheating, I just thought it was using too much coolant, as I have to top up the coolant reservoir almost every time we go out. But there have been no warning alerts on the dash about overheating, and no error codes that I can see. However, on Sunday we had the boat out and we had 4 people and some added ballast in the back with a wake shaper on the side and my son was doing wake surfing when the boat just died from overheating. It wouldn't start again. We let it sit for 30 minutes and it started up again and we gingerly headed back to shore. We were completely out of coolant after filling it up on Friday. I may have the same issue as I am using the orange coolant that is recommended in the manual, however, the original coolant could have been green. I don't know as the coolant tank was empty when I got it. HI could flush the coolant, as recommended above, however, as I'm losing coolant, I'm assuming there must be some issue with the coolant system itself as it is supposed to be closed loop. My buddy has a different boat with the same engine (except his has the supercharger) and he says he has never had to add coolant, There is no real Scarab dealer in town, so no way for me to get the coolant system pressure tested. Does anyone know any other way to try and find out why I may be losing coolant and why the boat is overheating? Also, if anyone has any additional info on some of the points brought up in this thread above I would appreciate it. How do I check if the ride plate is warm? Where is this cap that the guy said he tightened, which fixed his issue? Where is the water pump located and how would I replace this? Apologies for the noobie questions, but just getting started in the Scarab world and on this forum so any and all advice appreciated.

 

[Luc Lafreniere]

Hi

So if your coolant is disappearing, then it's leaking somewhere. This can happen with a failure of the head gasket but very unlikely since our boats aren't that old. i assume you aren't seeing coolant in the bilge because you haven't mentioned it. That narrows down a lot of options. All the hoses are interior so you should be able to spot coolant in the bilge if they are leaking but worth checking all of them to ensure they are clamped properly.

Your coolant circulates through the ride plate which is in contact with water to cool it down. Make sure nobody painted that. it needs to be UNpainted.

The other obvious place it could be leaking is at the drain plug. Dead center on your ride plate below the jet nozzle. Hex key. Make sure it's snug! Careful if you remove it coolant will pour out immediately and fast!

The fact that you're losing coolant is why it's overheating. Solve that first. Overheating should then go away.

All of this assumes no coolant in the bilge so please confirm that.