Chris Craft Water circulation ?

[SS MAYFLOAT]

Basics:1977 280 Criss Craft outdrive(volvo 280) 350 Chevy with Criss Craft EX Manifolds. <br /><br />Had boat 4 years now. Seemed like the exhaust manifolds was too hot. Not enough to burn your skin.A pyrometer (thermometer) reads 160 F for the logs. The riser temp is 64.<br /><br />I noticed while the engine was running on the muffs that I had more water being dumped out of the riser water outlet (which is cold) than the exhaust outlet. I would estimate 60% out of the riser and 40% out of the exhaust. I plugged the outlet with my finger on the riser outlet, and then more water started coming out the exhaust.<br /><br />I don't think things are right. I didn't notice if the logs cooled down when I had the hole partially plugged, but I would think so if more water was then being diverted to the logs. <br /><br />What is up? Is there a thermostat missing somewhere? The engine does have one, operating temp runs at 160. <br /><br />Just to get it launched, I'm just going to use pinch off pliers to help divert more water to the logs instead of the risers. I'm not going to shut the water flow off completely to the risers.<br /><br />Thanks

 

[keelhauled]

Re: Chris Craft Water circulation ?

Are these manifolds the same as the old Chris-Craft Thermocon manifolds? If so, I believe the risers are supposed to remain cold. I went through this on a Chris Craft Lancer (283 V8) with a Volvo 250 outdrive. The problem we had was the risers were not getting enough water and the hot exhaust gases burnt holes in the exhaust hoses and bellows. <br /><br />I may be wrong or talking about a different setup, but I'd be leery about letting those risers get too hot!

 

[SS MAYFLOAT]

Re: Chris Craft Water circulation ?

These manifolds have Marine Power labels on them. I'm not sure about Thermocon. The risers run exactly what the lake water temp is. I just think that too much water is flowing through them instead of the logs themselves. <br /><br />I'm thinking about installing some thermisters on the risers and logs to monitor the temps.<br /><br />My exhaust riser outlets are diverted into a cast iron elbow pointing the exhaust/water downward. This area seems to run fairly warm, but the riser itself is lake temp. I just feel uncomfortable with the logs running as hot as they do. I'll try to take a temp reading on them once I start playing around with a pair of pinch off pliers.<br /><br />The water that goes to the risers comes straight from the freshwater pump. There doesn't seem to be any thermostat's or restrictor to meter on how much flow goes through them. I still tend to think something is missing. I'll try to get some part numbers from the manifold/risers so that you know what I have. Thanks

 

[keelhauled]

Re: Chris Craft Water circulation ?

Came across one of the Thermocon Chris-Crafts the other day... There were little tiny thermostats in the risers! Perhaps these are what are missing on yours?

 

[yoced]

Re: Chris Craft Water circulation ?

Really thermostats? Or were they pressure relief valves instead?

 

[keelhauled]

Re: Chris Craft Water circulation ?

Good question... they look like thermostats... but what do I know?

 

[yoced]

Re: Chris Craft Water circulation ?

SS: What model Chris Craft do you have?<br /><br />(btw, Marine Power was a generic label everyone used back in the day - to distinguish from Industrial Power or Farm Power. Marine Power the engine company came along much later and wisely used those words...)<br /><br />If you are unsure I would ask:<br /> a) Flywheel forward or aft?<br /> b) If Forward do you have the Intake with the odd thermostat housing in it?<br /> c) Do you really have risers, or just drop elbows?<br /> <br />In any case, I would have you first look for a malfunction in the pressure relief valves on your risers. These valves were meant to divert any system pressure over *2 pounds* overboard through the risers. This sends a LOT of water overboard, and yes your risers for that setup would always be quite cold.<br /><br />If these valves fail they could be letting even more water overboard, meaning less water for the rest of the engine. If the valves failed years ago and someone took them out without saying so, then again too much water is going overboard compared to the water going into the circulator pump.<br /><br />If this is the case, then with the model information we may be able to come up with a flow diagram that can help solve your problems.<br /><br />If you want to talk with some folks with a lot of leftover Chris Craft parts and expertise, I would suggest Midwest Marine out off the Lake St Clair a bit to your north.