Want to try a cabin engine heater off of the fresh water cooling system.

[Bill with a seaswirl]

So what I mean is a set of hoses to a cage with a fan, aka car heater style. I would run good hoses with anti rub protection. My worry as I am thinking it through is the engine might be to cooled? Probably overthinking stuff again...

 

[Bondo]

My worry as I am thinking it through is the engine might be to cooled?

Ayuh,.... Welcome Aboard,..... No more so than yer car in the winter time,....

 

[Scott Danforth]

you can buy a complete kit. iBoats sells them http://www.iboats.com/Boat-Parts-Ac...er--searched.1--session_id.469638157&q=heater

the little wax pill in the thermostat on the motor will regulate the water flow as needed. you could add a half dozen heaters and not over-cool the motor.

 

[thumpar]

I was going to put one on my last boat but then sold it first. There was a new heater core in the garage I was going to use. What engine do you have? On some you need to drill and tap into the water pump.

 

[rallyart]

I have two 40,000 BTU units connected in series in my boat. They are a wonderful addition with not ill effects on the operation of the engine. My are made by Heatercraft. The only issue you need to concern yourself with is that the engine has to be running at sufficient RPM to flow water through the heaters. Idling won't put enough internal water pressure to do that well.
Water to the heater from the manifold just before the thermostat. Water from the heater to the suction side of the water circulation pump.

 

[oldjeep]

Plenty of kits available. There is an add on piece called a low idle Wye that takes care of the no heat at idle problem. For whatever reason they never seem to include it in the kits or the factory installs. Mine has a factory 3 outlet heater under the drivers console. Only downside to heaters is that you need to take special care winterizing them.

 

[Bill with a seaswirl]

Thanks for the insightful replies!

 

[frantically relaxing]

Just plumb the heater core like they do hot/cold transom showers: remove one of the drain petcocks off the block, replace it with 3/8" hose fitting... pick up a SMALL electric water pump, connect a hose from the block fitting, then to the pump, then from the pump to your heater core. The exit water from the heater, just run overboard (thru hull or whatever). Wire a switch for the water pump to an ignition-on circuit- The engine has to be running for the water to be hot, so engine off always equals pump heater off. If you find the water flow is too high, you can restrict the water flow from the engine to the pump with a small valve or any type of clamp that will work to squeeze the water line (even a small C-clamp will work)...

 

[oldjeep]

Just plumb the heater core like they do hot/cold transom showers: remove one of the drain petcocks off the block, replace it with 3/8" hose fitting... pick up a SMALL electric water pump, connect a hose from the block fitting, then to the pump, then from the pump to your heater core. The exit water from the heater, just run overboard (thru hull or whatever). Wire a switch for the water pump to an ignition-on circuit- The engine has to be running for the water to be hot, so engine off always equals pump heater off. If you find the water flow is too high, you can restrict the water flow from the engine to the pump with a small valve or any type of clamp that will work to squeeze the water line (even a small C-clamp will work)...

Depends on tour boat. Modern engines have knock sensors in those block drains.

 

[frantically relaxing]

Umm--sensors or not, the blocks have to drain somewhere, yes?

 

[spoilsofwar]

One, if any, of the drains would have a knock sensor. Not sensorS. And that's assuming it's a fuel injected engine of a certain vintage, of which we don't know, because the OP has not told us what he's working with. Chances are high that a knock sensor on a block drain is not an issue. And even if he had one there; use another spot, if you want to use this method.

 

[Bill with a seaswirl]

So, after reading your replies. My bad, it's a 98 250 aft cabin/ cuddly seaswirl with a 5.7. Just got the boat. Motor wasn't in it... Just got the motor. I have a thread going in the penta I/o section. Fresh water cooled from San Juan eng, the kit is on my porch. I would like to cool the manifolds also with fresh water since they are brand new and I will call the company in the am to see if a larger cooling system aka a heater core and long hoses will work.

Money pits is the right term for a boat!

 

[thumpar]

I wouldn't add a pump for the heater core. You already have a circulating pump on the engine. Here is the stock hose locations.

 

[oldjeep]

Umm--sensors or not, the blocks have to drain somewhere, yes?

Uh, yeah. You remove the knock sensors to drain the block - one on each side

 

[Bill with a seaswirl]

I wouldn't add a pump for the heater core. You already have a circulating pump on the engine. Here is the stock hose locations.

Very helpful! Thank you!

 

[thumpar]

Uh, yeah. You remove the knock sensors to drain the block - one on each side

Not on mine. There is a drain plug in the sensor fitting. There is only one sensor though. It is on the starboard side.

 

[oldjeep]

Not on mine. There is a drain plug in the sensor fitting. There is only one sensor though. It is on the starboard side.

Yeah, older engines only had one the newer ones have one on each side.

 

[Bill with a seaswirl]

I spoke with one of the engineers at San Juan engineering about this being a viable option for making it a full freshwater cooled system. He said no way. He is probably right lol. He did say running a heater line off of it was "not advised" it should be fine.