3208 NA running warm

Sykes · Feb 10, 2021

So new to me motor was running warm. I had a mechanic come out and he looked the motor over, ran it up to temp and used a IR gun to get a accurate temp. He says "change your gauges and sensor". Talked to two other mechanics and they said, open up the heat exchanger..

Well here is where we are at. Taking it out and to a specialist who only does radiators and heat exchangers today..

Originally I was shooting for acid wash / barnacle buster, sure glad i opened it up and didnt take the easy way out.

Sykes · Feb 10, 2021

Sykes · Feb 10, 2021

sorry cant get image to post, heat exchanger was blocked 80% by old impellers

High Wire · Feb 10, 2021

Believe your instruments until proven wrong.

FF · Feb 10, 2021

"sorry cant get image to post, heat exchanger was blocked 80% by old impellers"

On any boat a Y strainer installed AFTER an impeller pump is great insurance.

High Wire · Feb 10, 2021

Sykes said:
sorry cant get image to post, heat exchanger was blocked 80% by old impellers

https://ibb.co/R0p3N6F

That will do it!

ghost · Feb 10, 2021

Get a new mechanic while you are are at it, that was just plain irresponsible, not just dumb.

Good check to get in the habit is to check the exhaust water flow every time you fire up. Get calibrated to the flow.

Mine was plugged with calcification that badly when I first got it. We did a 300 mile trip before checking, but running at hull speed never overheated. Replacing the thermostats brought the temps to a very consistent level, but that was a bit of a job.

You will also need to pull the exhaust hose off the risers and get a visual on the small holes in the shower head. Don’t be surprised if you have to take a screwdriver and free half of them from rust buildup.

Sykes · Feb 10, 2021

ghost said:
Get a new mechanic while you are are at it, that was just plain irresponsible, not just dumb.

Good check to get in the habit is to check the exhaust water flow every time you fire up. Get calibrated to the flow.

Mine was plugged with calcification that badly when I first got it. We did a 300 mile trip before checking, but running at hull speed never overheated. Replacing the thermostats brought the temps to a very consistent level, but that was a bit of a job.

You will also need to pull the exhaust hose off the risers and get a visual on the small holes in the shower head. Don’t be surprised if you have to take a screwdriver and free half of them from rust buildup.

Going to look into that as well, risers, looks like we have had the same issues. Ive not put 8 hours on it since i took possession in August. Many little things to address, nothing to serious.

While i was at it today i looked into the gen's HE and found two more impellers. A/C needs a larger drain, list go on and on, but im knocking them off...

markbarendt · Feb 11, 2021

FF said:
"sorry cant get image to post, heat exchanger was blocked 80% by old impellers"

On any boat a Y strainer installed AFTER an impeller pump is great insurance.

Good thought.

sunchaser · Feb 11, 2021

Even better than a Y strainer is the practice of changing impellers well before failure. Suitably sized Y strainers are large and fraught with their own issues.

bayview · Feb 11, 2021

mechanics rarely look for missing zincs or impeller pieces. I suspect it is because owners complain when costs are more than original estimate and they will get more business later when something goes wrong.
You could insist and pay for inspecting the system when changing impellers or zincs but who does?

That is why I do my own work.

markbarendt · Feb 11, 2021

sunchaser said:
Even better than a Y strainer is the practice of changing impellers well before failure. Suitably sized Y strainers are large and fraught with their own issues.

Ok, I'm curious, what issues?

sunchaser · Feb 11, 2021

markbarendt said:
Ok, I'm curious, what issues?

In the raw water circuit they scale up and require cleaning out. Adding one will increase the TDH leading to over heat potential if not sized right.You'll want a bronze or SS one, very pricey. Your impellers should never fail if you are proactive. And they are big for the gallonage you'll be pumping. If you've unlimited space they are indeed something to consider, but virtually unheard of on recreational vessels.

On WWII landing craft, beaching the vessel showed a good application.

Mischief Managed · Feb 12, 2021

High Wire said:
https://ibb.co/R0p3N6F

That will do it!

If your HE showed any signs of leaking (and the rust in that photo makes me think it might have been leaking) consider changing the end caps (or Bonnets as CAT calls them) on the HE. They are plastic and tend to warp making it difficult to seal them well. A new set is only around 200 bucks.

Sykes · Feb 12, 2021

Mischief Managed said:
If your HE showed any signs of leaking (and the rust in that photo makes me think it might have been leaking) consider changing the end caps (or Bonnets as CAT calls them) on the HE. They are plastic and tend to warp making it difficult to seal them well. A new set is only around 200 bucks.

will do, thanks

ghost · Feb 12, 2021

Sykes said:
will do, thanks

The ones in that picture looked like metal. There were two metal versions, iron and brass. Mine came with iron. Inspect the sealing surface that runs down the middle, they are comparatively thin and will be the first failure point. Mine fell apart at the first probing with a screwdriver.

I was able to source brass as replacements(those were not $200

), but I don’t think you can get them anymore. Only thing I recall about plastic, is to follow the torque recommendations or they can crack.

C lectric · Feb 12, 2021

Although I see you have found the likely cause of the heating up there are other potential causes that may crop up. The previous owner certainly was not doing a good job as broken vanes should have been noted and chased.

I have posted my tome below for future use. It might be usefull.

Sykes · Feb 13, 2021

C lectric said:
Although I see you have found the likely cause of the heating up there are other potential causes that may crop up. The previous owner certainly was not doing a good job as broken vanes should have been noted and chased.

I have posted my tome below for future use. It might be usefull.

Awesome read, thank you

3208 NA running warm

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