Another Overheating Post

[Round2]

Hello my Epic Friends - I have a strange one for you.  I have Bullet's old boat.  Its a 2001 SX, about 850 hrs.  I bought it from him about 4 years ago.  Boat has slowly started to run hotter and hotter each year and this year its seems to have peaked.  So I just recently changed the timing belt, water pump and added the Stant 170 themostat.  On the plunger, it runs 160-ish all day long even at 1800 rpm (not in gear).  Water out the exhaust as you would expect. On the lake (in GA, warm water) at idle it holds 170-175 all day, rev it to 1800 or so, cools slightly.  As soon as I put it in gear no mater what the RPM it climbs quickly to 210+.  Stop, take it out of gear and it slowly drops to 175 again.  (no electrical accessories on)

While at the lake, I pulled the hose after the raw water pump to check flow and it seems fine (similar as on the plunger).  I also pulled the hoses on the front of the exhaust manifolds, decent flow.  Risers do heat up but can put my hands on them just can't leave them there long. 

Next step is to pull the exhaust hoses (not original) to look for de-lamination.  Also looking at installing a mechanical temp gauge to ensure proper readings. 

Anyone seen this before?  Under any load the temp climbs.  Could water flow be restricted in the block? Any ideas, help is appreciated.  This is keeping me up at night.  Thanks!!!

[Capt Rick]

Do you have a heater or shower ?
Sucking air from above items and or restricted flow to oil cooler
Check and put clear hose between heater pipes near electrical cover...
Capt Rick

[Round2]

Thanks for the reply Capt Rick.  No heater or shower.  I was thinking restricted flow as well (or sucking air from a leak) and was going to run a clear pipe from the lake intake all the way to the raw water pump to see if that solves the problem.  Can I run the boat for a few minutes without water running through the two oil coolers (one over the v-drive and the one under the motor)? I would bypass them both. 

Does water run through the heater pipes all of the time (if not capped)?  I believe they are capped right now. Will I be able to see the engine block flow at that point?  That would be great.  I could even add a temp gauge there.  Will look at that tonight.

Thanks again for the help!!

[ootyboy]

Do you have a closed or open loop cooling system?  For my situation I have a closed loop system and had similar overheating issues as described in the previous post.  I did try the clear tube trick that Capt Rick suggested and I was truly amazed at the amount of air bubbles that came out of the cooling system. I ran the boat for about 30 min on a fake a lake and again on the lake a day later. Based on my tests this weekend the boat is running a lot cooler and has normalized.   

[Round2]

I believe its an open system.  Lake water runs directly through the engine.  I'm going to try the clear hose this weekend to see the flow (and maybe air).  I never even thought to use those ports.  Great idea.  Fingers crossed it helps at least move closer to a diagnosis. 

I may also put the old thermostat back in.  The Stant is significantly different than the original.  Not sure it will make a difference.  Can you run the boat without a thermostat? I've looked around the forum but haven't seen anyone that has pulled it out altogether. 

Thanks again for all of the help.  Hopefully I make some progress this weekend.  Summer is winding down quickly and I miss the lake.

[ootyboy]

Here is a photo and video of trying to burp the system using the clear tube that Capt. Rick is talking about.  This is one of the many large air bubbles that came out of the cooling system. 

As you can see we our boat has a closed loop system, however,  I think this should apply to open systems as well.

https://youtu.be/s-IB2WKfHRs

[Round2]

Thanks for sending!  I didn't realize you put the hose up that high.  I also thought there would be more flow.  This was super helpful.  I'll let you know the result for an open system. 

[ootyboy]

The hose has to be long enough where you can create an air pocket for the air from the cooling system to escape. Also this was at idle, when I revved the engine to 2000 RPM the coolant would flow over to the other side.

[Round2]

Well I hooked up the clear hose to the heater ports and at first couldn't get any flow.  Then after messing around with a few things it broke open (or maybe the thermostat opened).  Now have great flow through the pipe even at idle.  On the fake a lake plunger the engine ran fine with a few bubbles running through the pipe but nothing major.  Temp stayed around 160.  I thought we had a break through.  As I was about to shut it down I accidentally leaned on the throttle and revved the engine past where I would normally.  It blew a ton of bubbles / air through the clear tube.   

Then I put the boat on the lake.  Same thing.  At idle and low RPM, limited air bubbles.  But run it up to 3000 or so and the clear tube is almost half air, half water.  So I'm definitely sucking serious air from somewhere. 

I added a clear hose between the strainer and the v drive cooler and there's no air entering from there.  Solid water the whole time.  So my air leak has to be between the inlet of the v drive oil cooler and the heater lines. 

Has anyone had experience with common places to suck air?  Can I be sucking air at the internal water pump?  Its not leaking. I know Cyclone mentioned a few places on the engine in his other posts.  No shower or any other aftermarket ports in the lines.  There is no water dripping from any of the inlet hoses or heat exchangers that I can see.  Can I possibly be sucking air after the raw water pump?

Anyway - I'm going to start replacing hoses and looking for air leaks but I'm open to any suggestions.  Let the hunt begin.

Oh - One more thing.  I've noticed we take on a lot of water while sitting in a cove.  Its not the packing, and I don't think its the exhaust.  I haven't been able to find the source and have been all over and under the motor while on the water.  Wondering if the issues are related. 

Thanks for the help Capt Rick and ootyboy.  I now know what the issue is.  Now I have to find the source. 

[Sammamish Skier]

Check the drain on the oil cooler for the transmission
 Perhaps it wasn't reinstalled after winterization. Note that not all of the coolers have drains

[DENNIS]

Hi Round2, did you ever find out where the water was coming in while the boat was sitting? 

Thanks Dennis

[cyclone]

Also, just change your exhaust hoses. Search the forums, get the ribbed ones, you can bend them. They are falling apart, guaranteed. replace them.

[Round2]

Sorry for the slow updates.  Haven't had enough time to work on the boat.  However, this weekend I was able to get clear hose on all sections of the suction side of the raw water pump to look for air.  Hooked it up to the plunger in the driveway and saw a lot of bubbles at higher RPMs.  Wasn't sure it was from a leak or from a bad seal on the plunger so I headed to the lake.  When on the lake, I saw bubbles all the way through the suction side so it may be a bad seal on the sea strainer.  Truthfully, I almost hope it isn't.  Otherwise I wasted some serious time on a sea strainer issue.   I messed with the strainer to try to create a better seal and nothing changed.  So I just ordered a new one to see if switching it out helps. 

Interestingly enough, changing all of the hoses out seems to have helped already.  The motor ran about 184-189 for a while at 3300 RPM.  So some progress.  Also, I feel like there is way more air in the clear line I put on the heater ports than there is in suction lines from the lake.  I guess once I get the air leak figured out on the suction side, if I still have air in the heater line, I'll start chasing other leaks. 

As for the water leak, I sat in a cove today and I crawled all around the motor and exhaust searching with a flashlight.  I did see some water coming in from under what appears to be a fiberglass fitted exhaust pipe that fits under the motor.  It looks like bullet may have tried to patch it and its coming undone.  Can you still get that part?  And even if you can, can you put it in without pulling the motor out?  I still don't think its the only leak though.  I was in the cove for maybe an hour and the bilge pump ran for a good minute to get the water out. 

Anyway, making some progress.  And thank you again for all of the help.  I wouldn't have gotten this far without it.  If I get this issue figured out, new exhaust pipes and parts are the winter project!

[Capt Rick]

Fiqure 21 part number 11

EX0011543   Pipe,ExhaustSystem,OvalShaped,S22,SX22,FRP,B   21    11    240.89    30.00

To repair it with marinetex or fiberglass is easier. Otherwise you have to remove engine.

Capt Rick

[Round2]

Thanks Capt Rick!  That's what I thought.  Maybe a winter project.