Inboard performance

[Randall Schmidt]

I have a 1984 Oday 28 with a 10 HP Universal Diesel inboard motor (now know as Westerbeek). I've been having over heating issues and getting help from 2 marine engine shops. Replaced thermostat, heater hoses, impeller, radiator cap and removed and cleaned out the exhaust manifold. Shop says keep her revs down but that is nonsense. They say keep it under 2800 RPM. It overheated at 2400 RPM after running for about 25 minutes at a speed of 5 MPH. I'm curious what experience others have this motor and what is a reasonable RPM level and speed to expect in calm seas. Also, any other ideas on overheating causes? I'm ready to consider a new motor to support my 1900 mile long ICW trip next year. A fellow cruiser told me he bought a new inboard for a larger sailboat for $6000. Sounds cheaper than I'd expect. I wonder what options I'd have to hookup to the same transmission. I just replaced the shaft and want to preserve the investment.

 

[Davidasailor26]

Do you have good water flow out the exhaust, and has the heat exchanger been inspected and cleaned?

 

[agprice22]

How about the raw water intake? Is it clear? That and what Davidasailor26 said...

 

[Davidasailor26]

Just thought of one other thing... How do you know it's overheating? Is it possible it's just the gauge or sender reading wrong? What is the temp going up to, and have you checked the temperature around the fresh water pump with a contactless thermometer?

 

[Ran-Dee9229]

Thanks for the ideas. The contactless thermometer confirms it is overheating when pointed to the thermostat housing. The temperature goes off the scale hot and the engine compartment smokes and you feel the extreme heat. In the past when she overheated I maintained good water flow but I did not look this time as I was in a narrow channel when she died and I was focused on getting a tow. I'm looking into the heater exchanger that I think my shop addressed earlier earlier but am not sure.

Any advice on appropriate RPM range for that motor, especially for a long ICW trip?

 

[SFS]

Do you have a copy of the operators manual? It should advise you on RPM settings. You may also want to pick up a copy of the shop manual, it could be a worthwhile investment in the long run. They may both be available online somewhere at no charge.

 

[jssailem]

If you impeller is ok. Did you do a replacement? Bad impeller sometimes leave bits of rubber. They drift into the hoses, pipes, and bends in your system causing blockages. Need to be sure the bits and pieces are not there. Next the closed coolant system. Is your coolant pump working? I had a BMW acting like a mechanic tell me everything was fine with my engine, only to discover the seal on the coolant pump was failing. Removed it cleaned up the gasket area. Installed new pump and gasket. New belts, and adjusted the alternator ( bolt was missing - again the BMW said no problem with engine). Put in new coolant fired it up, have over 30 engine hours and temp stays right at 163 running at 85% WOT. Best thing I ever did was to learn my engine and work with this forum to identify and resolve problems.

Your systems are simple engines.
Cold water is taken in it swirls around and out the exhaust.
The coolant system is closed. It has a tank, fluid is pulled out pushed around the engine through hoses and returned to the tank. There should be no leaks it is sealed.

1. Sweet burnt smell engine coolant leaking. Find it.
2. No or low volume water out exhaust blockage. Find it

Good luck. You can do this.

 

[odaydokay]

Second what others have said. Clogged or shot heat exchanger, partially clogged delivery hose from water pump up to it or the water pump itself is not delivering right. Start by pulling the hose off the pump to the HE, blow out and then pull the end cap off the HE right near where that hose attaches. If you see blockage or crap this will raise the temp for sure.

 

[odaydokay]

I run in salt water and the HE's are good for maybe 10 years tops. I bought a new one last year with a bigger anode and CU Nickel construction. If the water pump is dripping try new gasket or have it rebuilt but for any long trip replace the impeller for sure and carry a spare on board always.

 

[Richard19068]

Based on my experience I'm guessing built up calcium in the heat exchanger. You mentioned cleaning out the exhaust manifold but not the HX.

 

[Jalepeno]

What is the previous motor running history?
Is your bottom and more importantly your propeller clean?
Many owners "over prop" their sailboats on the mistaken belief that they can go faster or that it is easier on the motor.

 

[odaydokay]

Based on my experience I'm guessing built up calcium in the heat exchanger. You mentioned cleaning out the exhaust manifold but not the HX.

Yes or a major blockage somewhere. I never got above 195 degrees when my HE was full of cram and some small blockage in the feed tube from the water pump.

 

[Benny17441]

You have two systems to inspect; the raw water cooling system and the closed circuit cooling system. The only component these two systems share is the heat exchanger. In the closed coolant system the most likely faults are a coolant leak or poor coolant flow due to a blockage in the engine cooling passages or in the heat exchanger. In the raw water system once again poor water flow is the main culprit. Check a blocked intake clam, soft hoses that may collapse or blocked hoses, fouled strainer if so equipped, a bad impeller that is not sealing properly or failing to push an adequate volume of water, air in the hoses or a blocked or fouled heat exchanger and exhaust mixing elbow. Check the water flow coming out of the pump that it is steady, that it is strong and there is no air coming with it. Also check the water flow leaving the heat exchanger and expect for a somewhat similar result as you got from the pump outlet. Any significan drop in flow would point to the problem area as an obstruction or a malfunctioning pump/impeller. Your engine should be able to run at maximum rated RPM without overheating.

 

[odaydokay]

Best thing I ever did was to learn my engine and work with this forum to identify and resolve problems.

Ditto on that. On the highway if something breaks, just pull over and call the wife. Not so easy on the water. Big sense of security and peace of mind if you learn some of the basics.

 

[Randall Schmidt]

I found the manual for the motor. I put a new temp gauge in that is accurate but she still runs at 220 in the slip with no load on. I tried removing the thermostat which made no difference. I tried the book's advice of pushing throttle to 3000 RPM momentarily a few times to bleed out air in the system and that made no difference. I will go for replacement water pump next. The impeller has been replace and exhaust manifold cleaned. I need to examine the heat exchanger. The manual shows a diagram of this part but I'm not yet able to locate or know how to access it where I'm thinking it would be - on the port side under the lazarette hatch. I'm guessing I need empty out the hatch contents and find some screws and brackets that hold a divider vertical board in place that separates the lazarette contents from the motor area. Once I get to it, what do you suggest I do to clean it out? It looks like a pipe in the diagram.

 

[Randall Schmidt]

Is this asbestus tape? do I need to change it if so and if so what would I change it to?

 

[Randall Schmidt]

In this photo I see the seal cooling system reservoir. Behind it is that asbestus wrapped hose/pipe and at the bottom to the left, could that be the heater exchange system I need to inspect?

 

[Randall Schmidt]

I have the Universal Diesel marine owners manual for my Model 12 10-HP 4-cycle motor.
Manual says "If hot water heater is installed (in my case there is one), all air must be removed from the lines and system to prevent overheating usually by means of an added bleed valve in heater line or expansion tank in the system" When I go to the boat again (in about 2 weeks) I'll visually inspect to try to locate this valve. I'd appreciate any tips on this. Do I need to take my lazarette contents out and see if there is a divider board to remove to get access to the bleeder valve?

 

[Randall Schmidt]

Reading the manual it sounds like the exhaust manifold and coolant engine expansion tank where I add coolant are one and the same thing. I was envisioning an exhaust manifold like I'm used to see on car motor. In the photo the top right is the coolant reservoir and the exhaust manifold, is that right? What is the procedure for cleaning out the exhaust manifold - does it normally require an acid dip?

 

[jssailem]

Randall
Have you seen this diagram of the closed coolant system (Fresh Water/Antifreeze system)
Fresh Water Circulation Diagram
All Models Except M-15
Normal Range 165 to 195� F

Sea Water:

1. Sea water enters through sea water inlet

2. Through sea water valve when open

3. Through sea water pump into heat exchanger to cool fresh water system

4. From heat exchanger to sea water overboard through exhaust port

Fresh Water:

1. Coolant (fresh water with antifreeze) is introduced into the system from the coolant section of exhaust manifold by removing pressure cap and filling manifold tank within one inch of lower rim of fill port.

2. Fresh water engine driven circulating pump moves coolant from heat exchanger through engine block circulating pump and thermostat back through exhaust manifold into heat exchanger to be cooled.

The manifold serves as the engine expansion tank to allow for expansion of coolant as it is heated. You also fill the system at this point. In some cases when hot water heaters are installed an expansion or surge tank may be required to prevent air from entering the system.

Should your engine overheat, first check coolant level to make sure it is not low which would cause air locks to develop. If air does enter the system, it may require a couple of fillings to remove the air pocket. A momentary increase of engine RPM to approximately 2800 to 3000 RPM may aid in moving the air from the system. In some cases it may require doing this 2 or 3 times. Do this just as you notice the temperature starting to rise above normal.

I suspect you can remove the manifold to give it a cleaning. and I would suspect a radiator shop could service it. Beyond my experience but is makes sense based on automotive experience.