Forced Air Heaters, using Engine coolant ...

[region4]

Can I plumb inline a round trip heater hose to the bow, and run hot engine coolant to a heat exhanger? Can the engine water pump handle that additional load, say of a 20' round trip loop? Or is this a bad idea? Warm feet would be a welcome addtion, during the winter boating season.

Mercruiser 165 inline 6.

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

Can I plumb inline a round trip heater hose to the bow, and run hot engine coolant to a heat exhanger? Can the engine water pump handle that additional load, say of a 20' round trip loop? Or is this a bad idea? Warm feet would be a welcome addtion, during the winter boating season.

Mercruiser 165 inline 6.

Ayuh,.... It very Doable, 'n relatively Easy,.....

Ya need a 1/2" port on the head or t-stat housin', Below the t-stat for the hot water feed line,...
'n ya need a 1/2" return port in the water circulatin' pump housin',...

The waterpump will never see added load, as it's done by pressure differential......
The head, 'n below the t-stat is of a higher pressure than at the circulatin' water pump housin',...

 

[fen-isl]

Re: Forced Air Heaters, using Engine coolant ...

I always wanted to do that. But also wanted to kinda replicate the defroster for a cars windshield. Seems some mornings the dew just keeps fogging up the inside of my windshield in the early mornings. But would need a heater core that could take the salt water.

Well maybe some day I will get to it, low priority with the little ones running around now

 

[funk6294]

Re: Forced Air Heaters, using Engine coolant ...

Take a look on Summit Racing they have an already made heater box set up with a blower and I think it's around 130 bux

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

Me too for early and late year boating , I have the small heater core with fan , housing from aux heavy equip. and wondered if I could plumb to little 1/8 npt plug I remove from thermostat housing with a valve after heater core to shut off and dump overboard closer to where I drive from ? I guess I stick a temp then pressure gauge in to see what's there . I'm trying on a 3.0 L mercruiser and heres a diagram close . workable or will hurt something from using flow ?

Ayuh,.... It very Doable, 'n relatively Easy,.....

Ya need a 1/2" port on the head or t-stat housin', Below the t-stat for the hot water feed line,...
'n ya need a 1/2" return port in the water circulatin' pump housin',...

The waterpump will never see added load, as it's done by pressure differential......
The head, 'n below the t-stat is of a higher pressure than at the circulatin' water pump housin',...

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

View attachment 217312Me too for early and late year boating , I have the small heater core with fan , housing from aux heavy equip. and wondered if I could plumb to little 1/8 npt plug I remove from thermostat housing with a valve after heater core to shut off and dump overboard closer to where I drive from ? I guess I stick a temp then pressure gauge in to see what's there . I'm trying on a 3.0 L mercruiser and heres a diagram close . workable or will hurt something from using flow ?View attachment 217311

Ayuh,.... Donno exactly where that hole is,...
'n I'd have to look over a 3.0l to know for sure if there's a tappin' in the head you could use,...
The tappin' needs to be 'tween the head, 'n t-stat,... or from the head,...
Beyond the t-stat will be cold water when the t-stat is closed,...
Before the t-stat is heated water,...

1/8" is pretty tiny, meanin' a low flow,...

Also, dumpin' over-board will sorta defeat the t-stat, causin' a constant by-pass, which could cause the motor to run cold,...
Never tried it though,...

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

It looked like this one , and I thought the valve where I dump coming out of heater core I could throttle/restrict for pressure differential or hold heat before dumping overboard . The lines on heater core aren't as big as auto for equip had small cab and two for the area . I
'l try next spring as I know I want /think about heat in my boat again . My old 120hp Chrysler ran with stainless washer in place of thermostat for trolling only after 25 min idling it would alarm hot and all I did was idle up in neutral till it quit buzzing and be ok for same amount of time only difference was really cold lake water .

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

View attachment 217324 It looked like this one , and I thought the valve where I dump coming out of heater core I coujd throttle for pressure differential or hold heat .

Ayuh,.... Look that housin' over more closely,...

I'm thinkin' that plug is on the cold water side of the t-stat,...
On the raw water side, before it enters the block,...

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

I couldn't resize pic from manual I copied for the flow and lost trying to resize w/paint , I'll have to find again as it had flow and where its hot and cold.

Ayuh,.... Look that housin' over more closely,...

I'm thinkin' that plug is on the cold water side of the t-stat,...
On the raw water side, before it enters the block,...

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

The 1/8 plug looks like its for a high temp alarm sending sensor , I remove it when winterizing and it lets the block drain in less then 3min .
The pics at top seems to show some sort of bypass hole in the thermostat housing around it . I bought a new stat and gasket from when I thought it rusted out and ran cold and ended up in big hose only to find spiral wire in to keep it from collapsing from suction? I'll try to resize pic cause I don't remember seeing it in tstat housing.

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

I couldn't resize pic from manual I copied for the flow and lost trying to resize w/paint , I'll have to find again as it had flow and where its hot and cold.

Ayuh,... The housin' is a split flow, the in-comin' water enters through the fittin' seen, 'n allows excess water to flow out, or to the circulatin' water pump, which goes into the block, 'n stopped by the t-stat,...

In yer picture, an iron wall can be seen, ahead of the Hot water pocket,...

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

Thanks I didn't mean to highjack but heater in fishing boat should be option as I have been kicking this can down the road on April and now November in NE Ohio as it might be common in Alaska ?

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

Thanks I didn't mean to highjack but heater in fishing boat should be option as I have been kicking this can down the road on April and now November in NE Ohio as it might be common in Alaska ?

Ayuh,.... While it is a Hy-jack, region4's I6 is comparable in the coolin' system to yer I4,....

So the info exchanged is applicable,..

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

Ayuh,.... While it is a Hy-jack, region4's I6 is comparable in the coolin' system to yer I4,....

So the info exchanged is applicable,..

Ayuh,.... It very Doable, 'n relatively Easy,.....

Ya need a 1/2" port on the head or t-stat housin', Below the t-stat for the hot water feed line,...
'n ya need a 1/2" return port in the water circulatin' pump housin',...

You have hit nail on head seen ,used or installed before saying relatively easy . Hoses too? , Does your current boat have one ?



I found a Pdf manual for Maxium Boat and it has a Mercruiser Service Manual #26 that I had found that flow dia. It explained how , even Engine , Got to love the intranet , I'm not comfortable about adding hose fittings in big hose to suction of engine water pump for my return line , haven't looked at water pump might be plug on it in casting , the pressure side would come from tstat housing but needs opened up to 1/4 npt maybe , 5/8 hose max size and they don't make a kit for this engine it said . Thanks for input as the heater would extend my season .

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

Ayuh,.... It very Doable, 'n relatively Easy,.....

Ya need a 1/2" port on the head or t-stat housin', Below the t-stat for the hot water feed line,...
'n ya need a 1/2" return port in the water circulatin' pump housin',...

You have hit nail on head seen ,used or installed before saying relatively easy . Hoses too? , Does your current boat have one ?



I found a Pdf manual for Maxium Boat and it has a Mercruiser Service Manual #26 that I had found that flow dia. It explained how , even Engine , Got to love the intranet , I'm not comfortable about adding hose fittings in big hose to suction of engine water pump for my return line , haven't looked at water pump might be plug on it in casting , the pressure side would come from tstat housing but needs opened up to 1/4 npt maybe , 5/8 hose max size and they don't make a kit for this engine it said . Thanks for input as the heater would extend my season .

Ayuh,.... I've installed several, though all were on V-motors, 'n not I4s, or I6s,....

I'll have to go look at an I-motor, but I'm pretty sure there's a threaded port in the head which can be used for supply,...
'n, I'm pretty sure that Some of the circulatin' pumps have an extra port,...
But again, I'll have to go Look,... Maybe not,...

 

[Bondo]

Re: Forced Air Heaters, using Engine coolant ...

Here's a circulatin' pump with the extra port,...

Here we go,....

In that picture, the pump has the port, 'n the t-stat housin' has an extra 1/2" port, right next to the temp sender port,...

A work-a-round for the t-stat port is to "T" the temp sender, 'n use it's port,...

 

[jimbo_jwc]

Re: Forced Air Heaters, using Engine coolant ...

Going to install before global warming has us boating dam near year round like southern neighbors as I said thanks again Its doable even on little motors .