www.iFourWinns.com

Was after some advice...

Yesterday I beached my boat but had to use the engine to get back out (on a falling tide). Needless to say I sucked up a lot of sand/mud into the raw water cooling and the boat started overheating on the way back to the ramp. Tried a few times to let it cool down before restarting and motored slowly until the temp rose again before shutting it down - but progress was too slow so I radioed for a tow.

Was about a 40min tow back to the ramp (at about 20knots), but when I got back ther there and restarted the temp remained normal. Took it home and ran the motor on muffs and temp was still fine! I'm planning to take it on a short test run today to see how it goes.

My question is, is this a blockage that is likely to have cleared itself, or shoul I be stripping down the cooling system to clean it out properly? (My problem is that I'm away on vacation with the boat and woul rather wait until I'm home to get the work done).

Any advice would be appreciated.

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2005 Sundowner 205

5.0L MPI Mercruiser, Bravo1, 3 blade Mirage SS prop

I would inspect the impeller. There is a chance that is worn down from pumping sand and still functionally, but only to enough to provide minimal cooling... i.e. running at idle.

On our lake the main boat launch and popular hangout are both shallow and sandy. Very common to see boats with your same problem being towed in most weekends.

Before you test drive it check the impeller, you don't want to heat up again if you don't have to. Also, I would be surprised if you have a blockage.

Good Luck.

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2004 - 288 Vista
Twin - 5.0 Volvo Penta GXi DP

In addition to the impeller, check your thermostat to ensure it's not blocked and still functioning. Just a suggestion. Good luck.

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-Tony
2016 Robalo R200 w/Yahama 200!

Previous boats:
2003 Four Winns 248 Vista - sold
1994 Sunbird Corsair 200 - sold
1980 Checkmate Predictor - sold

Some simple things you can do while on vacation...just need a wrench (mine is 1/2 inch) and screwdriver.....as stated, check the impeller...drain the manifolds and block just like winterizing and pull and drain the lower hoses that connect to impeller and water pump. Push small wire in drain openings in manifolds and block in case clogged.

You can pull thermostat easily too with socket set and reseal with gasket sealer. Then hook hose up to flush line in engine compartment if so equipped..do this with engine off and it may help backkflush thru the drive. Also check the water intake grills on drive unit to make sure clear.

I had vegetation sucked into mine before and was able to pull it all out.

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http://i1339.photobucket.com/albums/o71 ... wqm355.jpg


08' H210SS
VP 5.7Gi

Impeller, hoses, intake, better check it all. I know when I winterized this year that one of the drains was clogged with dirt.

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2008 Four Winns h180 Bowrider
3.0 Volvo Penta

2013 Dodge Durango HEMI

Most likely the wear plate in the impeller is scored, and the impeller itself is probably worn, to the point where it will not really overheat at first but the exhaust sys will get very hot while on plane.
I had this exact thing happen after getting stuck on a sandbar last summer. Replaced the impeller and all was fine. No clogs.
When I inspected it and looked at it carefully the wear plate was definitely scored and the impeller slightly worn. When running the the boat on plane, the engine temp was only slightly higher but the exhaust manifolds were about 30-40 degrees hotter so I knew there was a water flow issue.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Thanks very much everyone. I'll take on some of those suggestions. Particularly pulling off the thermostat and draining the engine etc. I'll also attempt the impeller/pump as I'm sure it's probably worn - but in a sundowner it's a pain in the @?&$ to get to as access is pretty tight around the bottom of the motor.

FYI I did drop it in the water today for a test run (the ramp is right next door to where we're staying on the Gold Coast). Motored around for about an hour and Temp on the gauge was perfect even on the plane with two people onboard, but it did heat up at WOT, so something is not right...

Also at one stage I was getting motor alarm (two beeps every minute or so). Not sure why. Temp, oil pressure ang gauges were fine. I had this once before when the drive lube was low. Checked the oil level an it seemed OK. Something else to chase.

Thanks again all - very useful!

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2005 Sundowner 205

5.0L MPI Mercruiser, Bravo1, 3 blade Mirage SS prop

Lou, what is the wear plate on the impeller assembly that you talked about? Is it part of the disposable impeller or a separated part?

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http://i1339.photobucket.com/albums/o71 ... wqm355.jpg


08' H210SS
VP 5.7Gi

The wear plate is usually a stainless steel plate that gets replaced when you replace the impeller. It usually comes with the impeller kit. Some years when I've done the impeller the plate doesn't even need replacing but if there are any scoring marks at all you should change it.
Here in this pic the wear plate is the lighter colored one of the 2, the darker one is the gasket that goes in between the impeller mount and the plate.

http://www.overtons.com/modperl/product ... 7Aod3BQA0g

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

If you ran for an hour I would suggest your thermostat is functioning just fine.

It is also very unlikely you have any sort of blockage.

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2004 - 288 Vista
Twin - 5.0 Volvo Penta GXi DP

On those engines its on the lower starboard side of the front of the engine right? I'm guessing that the rear seat or bulkhead is right in front of it...
On some boats you can remove the rear seats and slide them forward. When I rebuilt my boat I used a 2 piece rear bench seat that allows me to remove one half at a time depending on what I have to do. If its an oil change I remove the port side, if its a starter or fuel pump I remove the starboard side. Much easier than struggling with a full width seat. Do you have the bench seat or the jump seats on either side of the engine?

https://www.dropbox.com/s/9pz3pzuz8kuvm ... s.jpg?dl=0

The 2 halves of the seat go in front of this bulkhead, which also can be removed in halves. Much easier than the way FW built it.

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88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II

Thanks Alex8q4. You're probably right.
Took kids out for a tube yesterday and temp was fine all day (I stayed close to the boat ramp just in case). I will pull the thermostat off and back flush just in case. But the impellor might have to wait until I'm back home.

LouC, that' a great mod! Unfortunately my rear bench seat has a moulded engine wall which is part of the whole cockpit moulding. But I like your idea so much I'm gunna look to see what I can do similar.

Ric

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2005 Sundowner 205

5.0L MPI Mercruiser, Bravo1, 3 blade Mirage SS prop

I replaced the impellor and wear plates anyway and all seemed OK. However went out yesterday (tubing etc) and found it was getting hot after we came off the plane (i.e. reduced revs after being on load). We were beaching the boat a bit but wasn't sucking up too much sand etc, but later in the day we were overheating again (alarm sounding) and wouldn't cool down.

Seems like little or no water coming through the hoses from the risers. Overheats on muffs too now.

I guess I'll have to have a good look when we get home from vacation, but I'm starting to think it might be manifolds/risers as they are still originals (9yrs old in salt and fresh water). Although I would have thought it strange for both sides to block at the same time. Up until now they have been running very cool, but now both sides run hot.

Is it unusual for both sides to go simultaneously? Anyway I'll start from the bottom and work my way through the cooling system.

PS: I'm looking with envoy at those polished Stainless Steel manifolds/risers. Has anyone had any experience with them? http://www.ebay.com.au/itm/380371641036?clk_rvr_id=770323800984&crlp=1_262691&mt_id=641&sdc_id=1422338901z794627z43073b0a2430zz&mid=503315&fitem=380371641036&linkin_id=8081368&kw=%7Bquery%7D&crdt=0&sortbid=18

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2005 Sundowner 205

5.0L MPI Mercruiser, Bravo1, 3 blade Mirage SS prop

Are you familiar with the weep hole on your circulating pump? It's there to indicate an issue with your circulating pump. I would stick my hand in there after running the motor and make sure it's dry.

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2004 - 288 Vista
Twin - 5.0 Volvo Penta GXi DP

You're saying you checked flow from the hoses that feed both manifolds and not getting much flow there?
Then you should look at what was not checked after the last overheat. If you boat in salt water, its possible for the passages in the thermo housing to eventually neck down with rust and that can cause low flow. You still can have an impeller problem if you are still beaching the boat you may still be sucking up sand but not know it. I never beach our boat. If I want to go to a beach I would anchor it out and bring an inflatable.

Yes your problem could be clogged exhaust manifold water passages after that much time in salt. I have to remove them about every 5 years to clean them out. If the walls of the riser section are getting thin or the sealing surfaces are getting thin then you need to replace them. The stainless steel one piece manifolds are much better in terms of corrosion resistance but cost 2x the price of cast iron. One piece design is nice because there is no joint/gasket to leak. Here is what one of my one piece cast iron OMC V-6 manifolds looked like after 5.5 seasons in salt. Note that one of the water exits was totally clogged up.

https://www.dropbox.com/s/co8mqd4vi8qze ... w.jpg?dl=0

_________________
88 Four Winns 200 Horizon
4.3 OMC Cobra-4bbl
2002 Walker Bay 10/2012 Suzuki 2.5
2008 Walker Bay 8

1998 Jeep Grand Cherokee 4.0/Selectrac
2007 Jeep Grand Cherokee 5.7 Hemi/Quadradrive II