Clogged Cooling Passages

NoYouRelax

Recruit
Joined
Jul 25, 2013
Messages
2
First off I would like to introduce myself as new to boating as the new owner of a 2002 Pro Line 22 WA with a 200 Mercury EFI Saltwater. With all my Google searches I just had to join this forum....tons of great knowledge in this community! Also, I am an engineer with a lot of tools and a bit driven to figure things out....ok and cheap too when it comes to paying for service...lol

The first day with this boat was great with a 2 hour ride heading due north from Annapolis up the bay. On day 2, I picked up some mud and a resulting over heat alarm condition on day 3. The temperature runs at about 160 at the indicator. Here is what I've done so far:

1. Changed Tstats, poppet and water pump.
2. Flushed engine with lower unit removed from supply line and direct coupled hose
3. Flushed from hose connection at flush connection
4. Did both 2 and 3 above with Tstat port open to flow over engine covered in plastic
5. Flushed engine in reverse from Tstat ports
6. Head are hot to the touch but not confirmed with infared reading yet and starboard side is 5 to 10 degrees hotter

The Poppet valve, the pump and Tstats all functioned fine but cooling improved some with sequential replacement and test runs.

During flushing with Tstat ports open (flange removed), I noticed that the starboard head cooling flows about 40 percent lower than the port side. This was a very key find So I think I've pin pointed blockage in the cooling system on the starboard cooling passages. It also runs hotter to the touch.

I can currently run fine with the starboard heat sensor disconnected but, I get another alarm at WOT, and I stay away from that. The console temp reads about 160 F

What I would like to do before intrusive measures, is some form of vigorous flushing from Tstat port backwards, high volume and max pressure of 45 psi. I will also consider a compressed air blast.

Is there any know vigorous flushing process?
Is running at 160 F ok for nowin 87 degree bay temperatures?

How much of a job is it to start revealing the cooling passage at the head and probing the passages with wire? (I am about to buy the service manual)

Other probable next steps...Install a pressure gage use thermal device on heads on heads

Thanks in advance for advice and comments, but garden hose flush wont get it for now.​
 
Last edited:

Bob_VT

Moderator & Unofficial iBoats Historian
Staff member
Joined
May 19, 2001
Messages
26,103
Re: Clogged Cooling Passages

A few things come to mind. If the powerhead was ever removed they installer may have installed the gasket the wrong way or incorrectly. I have seen gaskets installed upside down and it blocked a passage. I am not sure about your specific motor but have seen it happen.
 
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