lets try this again- need some help

[Andy Greene]

I guess if we never ran into things we have never run into- this shzt would be easy right ??

So here is an odd one- freshly re-built CMB 90 Gold head- by a very reputable source. Motor fires and idles fine, but once in the water I noticed if wasn't making water after the 2nd lap- I'm normally pretty anal about watching for water from the output.

Bring the boat in and remove the water line from the rudder, clogged- unplug at inlet on W/J and flows fine. Water jacket seems clogged, no biggie- remove and replace water jacket(with new jacket) even tho there is no restriction to be found ????

Blow thru water line from rudder before tossing back in and its perfectly clear- run one lap and it stops making water again.

Bring it in and same deal,clogged in jacket again- motor cools down after five minutes and line is clear again, as tho something is swelling at temp and restricting flow. The odd part is , these are parts I have run on this motor for over 2 years with no issues ????

Suggestions ?? BESIDES -SELL IT TO ME- TRIPLE FACE PALMS- YOUR SCREWED.......

 

[julianconde]

andy change the water jacket,change the water lines and change the rudder pretty much change everything that deals with the water system and see whats happend after those changes.. that would be my suggestion.

Julian

 

[Andy Greene]

Water jacket and all lines where changed, the issue is isolated to the engine- I can pull the inlet line(to the engine) off when its hot- and blow through everything BUT the water jacket, after it cools for ten minutes or so- its all clear again to the exit of the boat. Its as if something is growing once it gets temp.I compared the head button to several other I have and they appear to be the same diameter in relation to the jacket .

 

[julianconde]

ok. what i would do as a test take a water jacket that you have and covert it to hydro. put a set screw on where the water exits on the motor and drill a small hole on the top of the water jacket and see if then water comes out thru the top. thats another avenue of approach..

 

[jeff baham]

andy drill out the water nipple and, or, then cut a groove in the head right where the nipple sets could be that the head is swelling . is there anyway you mark the head to water jacket while it fasten to the motor and then remove both and measure the space between the nipple and head.

 

[Hydro Junkie]

Jeff, an easy way to do that would be to take a black sharpie marker and blacken the head inside the jacket. Next, take a scribe or small drill bit and scratch the head enough to remove the black ink. You can now see where the nipples are in relation to the head. The nipple may have to be removed to fit the scribe/bit into the jacket but that's not normally a problem.

 

[Andy Greene]

Thanks guys, trimming the head button down near the inlets is my next step I guess. Visually looking at the clearance between the water nipples and the head button - it appears to have a ton of room. The only other thing I can thing I can think is that I'm loosing combustion and its pressurizing the water jacket till it cools down - the question then becomes, How do I confirm that and how to fix it ??

Andy

 

[dwilfong]

Andy ether there is room or there is not nothing in that eng will grow that much.

How much clearance is there at the nipples to what ever there is in front of them on the inside?

 

[Andy Greene]

They are flush with the inside of the water jacket Dave and I agree , there is now way the button swells that much in one lap. Will post a pic in the am-

I dont get it..............

 

[Rick Sowell]

Andy, post a picture of the head and button in question, maybe we can see something you are overlooking. Rick

 

[moparbarn]

Andy, it's not compression or combustion issues. while that could over come to water pressure & stop flow, when the engine stops, so does the combustion. the pressure wouldn't stay in the water jacket, it would at least leak back into cylinder the way it came out. is it blocked at the outlet also? have you taken out or loosened the water nipples while it's hot & blocked? see if that opens it up. may at least eliminate 1 more thing so you can narrow it down.

 

[anthony_marquart]

are the nipples not sealing to the head when hot,.. then flowing water into the hull and the carb?

 

[ids987]

Deleted. Sorry, memory failure / misinformation on my part.

 

[Norm Doerr]

Andy, post a picture of the head and button in question, maybe we can see something you are overlooking. Rick

Exactly, pictures are a good idea.

Is this a Frankestien engine and or in the same configuration as a stoch engine? Maybe box it up and take it over to the engine builder's shop and let him or her figure it out.

 

[Andy Greene]

It's the original motor I had with a new sleeve and piston Norm.

 

[Norm Doerr]

That is not a stoch head button????

 

[Andy Greene]

That is not a stoch head button????

No .

 

[Norm Doerr]

Compare the dimensions to the old one. Also run some water through it and look for something strange.

 

[Charles Perdue]

Check the top of the case and see how far it is going up into the water cap. Using a different head button that is not tall enough may allow it to go too far in and block the water flow.

Charles

 

[Andy Greene]

Compare the dimensions to the old one. Also run some water through it and look for something strange.

Visually the look very close- I will mic it comparing it to the others I have and see.

Andy