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  Topic Review (Newest First)
01-21-2009 04:16 PM
jasongael so... story continues.. I got a tapered brass nozzle and shut off valve for my garden hose, and I clamped off the return hose (bypass), I put the nozzle into the crossover hose and connected the thermostat housing to a hose emptying into a bottle. But, i couldn't blast through that direction. So, I reversed it, putting the bottle on the crossover, and the nozzle into the thermostat housing and was able to blast it out. Then, I reversed it again, and was able to get flow. Once I flushed it a while, I put everything back together the correct way except I left the thermostat out, and started her up. She ran well and kept a good temp. A steady stream of water came out the exhaust, but not enough. Not even a steady pouring. So, I think maybe it got reblocked, and I'll need to flush it thoroughly and try again. I just don't want to use acid if I don't have to yet. I'll keep you posted! And thanks again!
01-19-2009 05:29 PM
jasongael awesome! yeah, I actually read your previous post and thought the approach was great. On page 35 of the previously mentioned manual, there is a diagram. My blockage is between the Engine to Manifold Crossover Hose, and the Thermostat. Somewhere in that circlular route, I am blocked completely. I've tested every other possible flow, and they all work perfect. It's just that one spot. So, I think, taking your advice, I will disconnect one end of the crossover hose (farthest from thermo), and restrict the bypass hose, and use the nozzle trick 1st. If I can't blast it out that way, I will .. very slowly .. pour Oxalic Acid in there and wait a while. Then, start the engine and cross my fingers. Thanks man! Isn't it great owning a sailboat???? ARrrrrrrr!
01-19-2009 04:17 PM
montenido Jason, try the oxolic acid trick, it worked for me. Get some of the acid at WM or some other place. Mix it up in a 5 gallon bucket. Disconnect the bypass hose that runs from the thermostat back to the raw water filter, at the filter end. Remove the thermostat and re-install the thermo cover. Hold the unattached end of the bypass hose above the motor and insert a funnel into the hose. You are now going to slowly pour the acid solution into this hose so that it enters your motor from the top. Before adding the acid, be sure to disconnect and plug the hose that runs from your water pump outlet to the bottom of the engine. I think the acid solution, although mild, might do harm to your impeller and pump. Let the acid solution sit in your block for a while and then reattach all hoses (you can install the thermostat later, just don't forget). Make sure your cooling intake thru-hull is open and start your motor. This should work. If it doesn't, try using a tapered brass nozzle on a garden hose and insert it into the end of hose that you have detached from your water pump outlet. You may also want to pinch off the return hose so that the water pressure doesn't push everything back to your raw water strainer. If you finally get water to exit your exhaust outlet while under power, you are almost finished. Re-install your thermostat (after checking to see that it operates properly) and re-connect all the hoses. Now go and motor around a while and make sure that water is still exiting out the back of the boat. I ended up installing a plastic ball valve in my return line so that I could regulate how much water bypasses the system.

I hope this helps. Send me a PM if you need more info.
01-19-2009 11:11 AM
WanderingStar There is probably rust or metal deposits blocking the flow.
01-18-2009 09:39 PM
jasongael Well, mine is a Universal 5411. You are correct, there is no heat exchanger. I have an excellent impeller. The pump IS pumping water fine. It even gets up to the top little short hose before the last leg to the thermostat. BUT, water does not get through that channel to the thermostat. I have already verified water will go out if I pour it down the expellation hose from the thermostat. I just don't have water getting through that last length of the block. So, question is: how do I unclog that part? All help is welcome. you guys rock!
07-31-2008 09:57 AM
SteveInMD Okay - you might want to look at a freshwater cooling conversion kit if you continue to have problems.
07-31-2008 07:26 AM
saurav16 the 5411 has no heat exchanger...
07-31-2008 07:07 AM
SteveInMD Have you removed and cleaned your heat exchanger core?
07-30-2008 09:13 PM
Re: Raw Water Cooling - Update

Hi all, just got back from the boat this afternoon. The short version is that everything works well now. The longer version is this: I used a brass high-pressure nozzle with a shutoff to pressure flow each section of the saltwater cooling system. Only felt some resistance once or twice. Knowing that everything was now clear, I reassembled the system and started the motor. After a minute or two of water coming out of the exhaust, nothing again. Damn, so I took apart the water pump for the 6th or 8th time since replacing the impeller and gasket. Everything looked fine, I even had my son crank the motor so I could be sure everything was turning correctly. Frustrated again, I pumped a solution of Oxalic acid through the block to remove rust scale, something I read about here. After flushing everything with fresh water and reinstalling the thermostat, I started the engine and what do you know, water was flowing from the exhaust port in a healthy stream. One thing that I had to do to make this happen was to restrict the bypass line that runs from the temperature sensor back to the intake side of the water pump. I will install a valve tomorrow so that I can control the flow there (I also read about doing that here). Motored all around the marina will nary a hiccup and plenty of water exiting the exhaust. So I am not sure which one thing that I did caused the improvement, maybe a little of each. Anyway, I am one happy sailor right now.

Thanks for the great advice everybody.
07-27-2008 11:48 PM
montenido Thank you everybody for the great ideas and advice. I have not yet gotten back down to the boat (my wife accuses me of being obsessed!!!!!). I will go through all the different parts of the cooling system from the sea-**** to the muffler. BTW, it is a Universal 5411. Sorry, I will include that important info in my next troubleshooting post.

Thanks again, and I will let you know how it pans out.
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