Dual Motors Overheating on Eliminator

I hope you will help me as I am in a loss as to what my problem is.

So I thank you in advance

 I have an 1987 23' Eliminator Daytona with 2 Mariner 2.4? 200 EFI's. I have sportmaster gearcases, and I am not sure of the props(3 blades) one engine is counter rotating. They are sitting on a 14" setback. I have just set the motors to where the nosecone is 1 inch above the bottom of the sponson.

The powerheads were replaced with factory new 1998 powerheads and the gearcases were added at the same time in January 2001.

I am having a overheating problem with both motors. I have replaced the impellers, thermostats and sensors, Lowered then raised the motors (manually). Put a manual temp gauge on just to see if my electronic gauges were working properly.

My water pressure does not seem to get above 10 psi.

If I run the boat at approx. 4000 rpm, at 3/4 trim. It seems to cool the motors of some.

I am currently replacing the gaskets on the bottom of the block and the spacer (donít know what it is called). Just to see if the gaskets were wrong. I donít believe they were.

So I think I am back to my original thought of the motors are not sucking up water.


As I bought this boat in the configuration it is in. I cannot give to much detail about what it was doing before. I have called the last owner about the situation. Found out he knew about the overheating but I believe he traded the boat off because he could not rectify the problem.

I bought it from a dealer. And donít have any recourse but to find out why it is overheating.

Any thoughts about what I could try would be very helpful.


And thanks again

Craig Parker
Killeen, Texas

 

Craig,

Here is my list of things to try.

1.    Make sure the gasket between the 2 motor plates (the ones that sandwich the upper motor mounts) is not blown out.

2.    Luckily, I just did one of these 3 - 4 days ago with the same problem. The problem all revolves around the pop-off valve on the bottom, starboard side of the block. I would recommend removing the pop-off valve assembly and replace it with the plate and elbow off of a 2.5 race engine. You can either dump this water overboard, or better yet, dump it into the fitting located on the portside of the exhaust adaptor (kind of under and ahead of the port cylinder head). Also, remove the thermostats and replace them with the restrictor washers from a 2.5 engine either 1/8 or 3/16 hole size. This setup will work much better with the Sportmaster cases and the heights you were running. The water as it is now is getting short circuited in the block and not absorbing the heat from the engine properly.

3.    Lastly, with the new Sportmaster cases, make sure the water tube and water pump diameters match. Mercury makes 1/2 inch and 3/4 inch tubes and I have seen them mixed up on boats before.

Give this a try as I do about 2-3 a year with the same problems.

Randy

 

 

Please submit whatever questions you have to IHRTechTalk@yahoo.com.  All questions and answers selected will be displayed on this page as they come in.  Note: though all boaters are welcome, priority may be given to I.H.R. members.  Randy can not be held responsible for any advice given.  Though his information and expertise is second to none, he has no control over what you do with your boat.  It is up to you to boat safely and act responsibly, and his advice is only to be used as a guidance for your high performance boat/motor of which you are the one responsible for the risks involved.

Thanks,
Mark C.

 

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