Clogged cooling system

[wgalmond]

Hi guys,
Having an issue with my port side cooling. I believe I have a clog somewhere just need to troubleshoot. Ran a ground slightly and kicked up a bunch of dirt/silt. Noticed the engine was running hot and the manifold and exhaust elbow on the starboard side only was very hot to the touch. Boat is on land now and I hooked up the muffs to the prop, and I can only see water coming out the exhaust on the port side (looking at the stern of the boat). No water is coming back out of the engine through the exhaust on the starboard. I disconnected the hose on the bottom of the manifold, and some silt came out. I thought what was it, but still nothing.

Anywhere else I should be looking for a clog?. Or how I can isolate where it is?

2000 Mercruiser, Alpha 1 Gen 2. GM V8. 305, 220hp.

Thanks guys.

[wgalmond]

UPDATE, I have since removed all the petcocks and specifically the one on the starboard side on the block had a lot of soot come out. I stuck a tie wrap gently up there, and then water and soot seemed to break free. I did this for all of them. Both bottom petcocks (port and starboard) seems to have crap come out. I put the muffs back on and started her up, but same thing. No water coming out of the starboard side exhaust. Still appears to be a clog of some sore somewhere.

Thanks,
Bill

[mmwjr]

With the startboard exhaust manifold hose off run the engine on the muffs, does water come out the hose? If yes the manifold and elbow are clogged and need to be removed and cleaned. If no the T-stat housing is probably clogged.

Note: do not run for long this way.

You can also use a IR temp sensor to measure different points to see what is normal vs. hot to help pinpoint the issues.

[wgalmond]

Thanks Mike, I will be going to the boat tomorrow to try that out. I will report back with my findings.

Bill

[mmwjr]

You can try to flush out the exhaust by holding a garden hose to the manifolds input however my concern is it may only clear out the center of the manifold and not the ends.

[wgalmond]

So do you mean removing the petcock plug and trying to shoot water in that way?

[jparsons121]

I think Mike is suggesting that you pull the hose feeding the manifold, so you can attempt to blow out anything stuck in the manifold...

In addition to the approach above, you can also determine if the flow is restricted leading to the manifold by checking the flow from the hose.. I doubt you will find an issue there as the port side is fed off the same feed (t-stat housing) as the starboard.

John

[mmwjr]

Originally Posted by jparsons121

I think Mike is suggesting that you pull the hose feeding the manifold, so you can attempt to blow out anything stuck in the manifold...

In addition to the approach above, you can also determine if the flow is restricted leading to the manifold by checking the flow from the hose.. I doubt you will find an issue there as the port side is fed off the same feed (t-stat housing) as the starboard.

John

+1 Yes pull the hose of the manifold elbow and hold the garden hose to it and try to flush it out

[wgalmond]

Ok, so I disconnected the hose on the manifold and put muffs on. Started up, and water was coming out of the hose just fine. So I attempted to shoot water in the manifold with garden hose...Didn't see any soot or anything come out. Started up again fully connected but same thing, no water out the starboard side. So we think it's clogged in the elbow or manifold somewhere? If so, what's next? Try to take that bit 4inch hose off the back of the elbow?

Thanks guys I appreciate the feedback.

Bil

[jparsons121]

OK.. So that eliminates the t-stat and points to a blockage in the manifold/elbow...

If you want to do some more testing, you could disconnect the exhaust hose and verify that water is able to drain from the exhaust hose out thru the transom/drive... Slim possibility that you may find that it's blocked..

Otherwise, I'd start to tear down the manifold/riser/elbow and verify the passages are all clear... You can't really back-flush anything at this point as there is a risk of water entering the exhaust and filling the cylinders... Not good...

John

[wgalmond]

Hi John,
Tearing down the manifold/riser/elbow looks fun (NOT...) but was thinking that is my next step. Also, I have been reading that you should replace the manifold/elbow/riser every 5-10 years on the long end, is that correct? The boat is a 2000, and I have had her for 6 summers now. I know I haven't replaced them. The previous owner had the boat 1.5-2 years and Im fairly certain he didn't either. The owner prior to that, pretty much had the boat on land for a few years when her husband passed away.

Question.....at this point in the season (New England =cold) Should I just winterize the engine manually buy draining all the water and loading her up with antifreeze? Then plan on replacing the manifold/elbow/risers in the spring? Looking at taking off them now seems a little involved (maybe not) but wondering if I should just go ahead and plan on that for the spring?

Thoughts?

Bill

[jparsons121]

Tough call...
Yes.. General rule I have always followed is to replace after ~5 years in a salt environment. I have a 1999 and have done this a few times.. It does get easier..lol

If I were back up in NE, I'd do it now... a) Freezing was always my biggest fear over the winter. Not knowing if there is residual water in the manifolds would drive me nuts worrying if I was creating more issues for the spring... b) Season is short, so I always tried to do as much work as possible in the fall so I could launch ASAP.

It's up to you, but leaving things would drive me nuts...

John

[mmwjr]

Remove the elbow, then but the garden hose into the rubber hose that goes to the overboard exhaust and verify water flows out the back.

With the elbow removed you can inspect its and the manifolds water jackets to see if they are clogged.

Note if the manifold is clogged its best to remove it to ensure crude does not get into the exhaust port, it will also be easier to clean this way.