2001 2100v (350 MAG/MPI) overheating/thermostat issue....

[h2osk8er00]

I have two problems now that I have done my spring maintenance and went out on the water... I do believe they are isolated and unrelated but I could be wrong...

A couple seasons ago I replaced my thermostat because the needle would show that the motor was maintaining the 175 degrees that it usually shows on the analog meter on the dash (I think it is really 162-165 or something), but would periodically jump down to much cooler temps throughout the trip.... It still does this even with the newer thermostat so I am now thinking there is a sensor not connected well... Any thoughts?

The other issue is overheating...I went to launch the boat and I noticed the belt was not turning well.. it was beginning to squeal and stop...so i killed the boat... tightened the belt after verifying each fully could turn well... still did it... thought about it again and think that the pick-up under the boat was on the bunker so maybe it wasn't getting enough water... launched yesterday... was out for about 20 mins... heard the squeal almost com back while idling... then came home to diagnose... think something may be caught in that mechanism right before the impeller assembly.. I have not gone through and impeller but maybe I sucked up some of the carpet from the bouncer board or something else? I am going to take it apart and start the troubleshoot fun but just thought I would reach out to my experts on here to help me out! It ran on the trailer with a hose okay... it would start to get a little hotter than usual but when I put it in neutral and throttled up a little I was able to get the temp back down... anyhow... thanks for the help everyone!

[Ruger761]

Sounds like the impeller needs to be replaced. I would pull it out and replace it. If there are any pieces missing you need to check by the trans cooler as they typically get caught there. You want to be sure to get all the missing chunks as they restrict the flow. Testing with a water hose wont test the impeller as it is pressuring the system.

Your temp will likely stabilize with the new impeller. Also this early into the season there are probably cold spots in the lake.

[h2osk8er00]

Def tons of cold spots but would that impact the impeller? Water temp is already 60 degrees... maybe 50 in some spots though... I just put a brand new out of the box mercruiser impeller as I replace it every year just because I like to have a fresh one with the new season... I will def check the transcooler though... that is what I think may be preventing the water from flowing well... not sure what could be in there but I think something is def blocking the water from flowing freely through there.... I heard the belt start to squeal when I was idling out on the lake... put it in neutral and revved it up a few times and everything stabilized... ran it about half throttle all the way home... seemed okay... temp was normal but it did feel as if I had the throttle slightly more forward than where the speed should have been... regardless, we got home just fine... it was as soon as I put it on the trailer that I heard the audible alarm for the temp... wasn't in the boat so I had my dad kill the boat really quick... got up to 200 though.. maybe hotter.. Thanks for he reply! I will let every one know once I am able to get in there and search some forums in the meanwhile.

[h2osk8er00]

UPDATE: Checked the trans cooler and it was wide open.. nothing in there at all... impeller was perfect too... good suction.... I am being told it may be the bearings in the sea water pump assembly.... It is the original one from the boat and I used to operate the boat in brackish water while boating in Maryland... regardless, I am not too sure what else it could be... It did appear as if it was kicking as much water as it usually does out the exhaust when hooked to the hose... could have been my imagination though. Had the boat for so long I feel a little lost because I thought I had it all figured out! JK.. Ordered the new part.. a refurbished one one e-bay ran $250 but it comes ready to install (new impeller and housing). Fingers crossed! Comes in Friday but I will be gone... Will update again as soon as I can but feel free to chime in as you all see fit! Thanks for helping an old owner out!

[sminto]

Have you tried replacing the belt? I had a similar issue last year with the squealing and random overheating (when the belt was just skipping) and even tried tightening the belt since it seemed loose. Once I took it off, I found it was actually split and pretty worn. With the new belt, I have no squealing anymore and hoping that once I can get it on the lake my problems won't come back!

Shawn

[h2osk8er00]

Belt is brand new and I did tighten it up... I am getting a new trans cooler as well it looks like... they are the only two parts left that could have been causing the problem and since they are both original to the boat I was told by my mechanic mentor that I should go ahead and take care of them. Expensive parts and hate not knowing but I have a good feeling this will be a good investment when all is said and done. More to report... BY THE WAY, Trans Cooler part number is 808029T for my boat... had to get help to find that number as well... THANKS CORY! https://www.mrcool.us/808029t-mercru...ar-cooler.html

Great prices at MrCool's website!

[h2osk8er00]

Got the trans cooler out and the sea pump pulley. Both will be replaced as soon as I get them. I was going to put the new pump on with the old trans cooler but Since I am headed to New Mexico it will have to wait.

18 years on these two bad boys and a lot of salt water. May they rest In piece. Just don’t make them like they used to though! That’s for sure. Approx 750 hours. Haven’t checked my hours since 2012 I think when it had 478...need less to say I don’t get out enough. This year will hopefully be different. Plan on doing an oil change mid season.


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[Ruger761]

At least they are pretty easy to change out, that's always a plus. Going ahead with the trans cooler will ensure you don't end up replacing the trans due to a cooling tube leaking as well.

[freeheel4life]

Just a friendly reminder, give your other pulleys a check as well while the belt is off, especially the circ pump pulley since your original complaint was overheat issues.

[h2osk8er00]

Just a friendly reminder, give your other pulleys a check as well while the belt is off, especially the circ pump pulley since your original complaint was overheat issues.

Thanks Freeheel! Got it all back together. Everything ran well. Temp is shooting down to zero every once in a while. Think it’s a bad ground. The new pump looked like the pulley was wobbly but everything ran smooth and I think it might have been the aftermarket paint job from when it was refurbished.




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[jamesbond]

H20 what kind of brackets you have for your bimini?


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[h2osk8er00]

H20 what kind of brackets you have for your bimini?


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It was meant for a thicker tower but my buddy and the bright idea of using bicycle inner tube to make up for the lack of width on the inner metcrap part of the tower. It’s a Westland aftermarket bimini I believe. Has served this boat well considering the stock one was a royal PITA and I haven’t had the money to put a new tower on.


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[freeheel4life]

Thanks Freeheel! Got it all back together. Everything ran well. Temp is shooting down to zero every once in a while. Think it’s a bad ground. The new pump looked like the pulley was wobbly but everything ran smooth and I think it might have been the aftermarket paint job from when it was refurbished.




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Glad to hear its ready for summer. You sure do have a beautiful spot on the water!! If the gauge keeps having issues but you arent overheating then it should be pretty easy to figure out.

Happy and safe boating!!

[h2osk8er00]

2001 2100v (350 MAG/MPI) overheating/thermostat issue....

So I thought it was fixed but still having the same issue where the temperature shoots down when the motor is obviously running and warmed up. I brought a temp gun and was able to shoot some temps near the thermostat and I got temps up to 185 which was what the dash had gotten up to as well. Not sure if this is abnormal or not. I know it used to sit right at 175 even though I know it’s a 165 degree thermostat, but that was before I had issue where the temperature would shoot down to zero. Regardless, I have replaced the thermostat 2 seasons ago, and the the trans cooler and the sea water pump to include a brand new impeller and housing this last weekend. I no longer have any squeal from the belt and I didn’t get any audible alarms for the temp and even if it did get up to 185 it did seem to cool back to 175 (on the dash) and I had no performance issues. It’s a mystery that I hope to solve but I’m not going to let it stop us from having fun. Boat is nearing 20 years old quick so I understand when these issues arise it may not be easy to diagnose, especially when I may have multiple issues that could be going on. Hopefully I have isolated it enough for y’all to steer me in the right direction. Here are some pics and a quick video of the temp issue. So far I have ran it about 2 hours (a lot of it at idle) and I have not had any issues. For the record, at idle, the temp shoots down as if the boat is cold.
https://youtu.be/-sReq2r3G4k

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[Ruger761]

You might double check the Tsat. That sure looks like it might be sticking or a slightly higher temp version vs the original 165. You can either replace it or if you can put it in a pot on the stove. Heat it up and check the water temp at which it opens up. As quickly as it’s bouncing temp I’d say your getting good flow now.