mercruiser 4.3 thermostat housing

[ste80]

good morning to everyone, i'm new in the forum. and thanks to have me accepted.
i have one querry for you all, ( i sow similar thread but it was not possible to reply there) i'm rebuilding one mercruiser 4.3 LX motor to be installed istead of mine old 4.3 EFI motor. ( so i still have a lot of EFI components available) i sow that my original LX thermostat housing is in very bad condition (rusty) and i was thinking to use the one from EFI model. The problem is that LX model has 6 Pipe ( 2 more for the riser) . i think i can use also the efi une, but not sure i need some exta modify,if it is better the EFI one or the LX one
what do you suggest

thanks in advance

 

[alldodge]

Welcome
Use all the components from the EFI on the LX. Use same exhaust manifolds and hoses. Don't use the older style

 

[Bondo]

Ayuh,...... Welcome Aboard,........ Which outdrive is being used,..??
Which exhaust manifolds are being used,..??

 

[ste80]

Ayuh,...... Welcome Aboard,........ Which outdrive is being used,..??
Which exhaust manifolds are being used,..??

hi; thanks a lot.
for the components i will buy for sure new riser, and probabilly also new manifoold. so i think i will use EFI model with tap on them

 

[ste80]

Welcome
Use all the components from the EFI on the LX. Use same exhaust manifolds and hoses. Don't use the older style

thanks a lot. if i understud well, on lx there are 2 ppe that goes on riser and the purpose is discharge the cold water? instead in the EFI model it will discharge only when thermostat open?

there is any other modify that i need to do? or just pump, pipe riser for EFI?
thanks a lot

 

[alldodge]

thanks a lot. if i understud well, on lx there are 2 ppe that goes on riser and the purpose is discharge the cold water? instead in the EFI model it will discharge only when thermostat open?

there is any other modify that i need to do? or just pump, pipe riser for EFI?
thanks a lot

Only think needed is different gaskets between manifold and elbow.

The LX used what was called warm manifolds and more cold water would flow out the elbow. The EFI changes so any water not used to cool motor goes out thru the mans then out the elbows

 

[alldodge]

Would use full flow Gasket

 

[Scott06]

thanks a lot. if i understud well, on lx there are 2 ppe that goes on riser and the purpose is discharge the cold water? instead in the EFI model it will discharge only when thermostat open?

there is any other modify that i need to do? or just pump, pipe riser for EFI?
thanks a lot

this is an ok outline of the differnce between warm and cold manifold systems. on both systems some water is flowing at all times to cool the exhaust regardless of whether the thermostat is open

Raw Water Marine Cooling – The Difference Between Warm Vs Cold Manifolds | PerfProTech.com

Large selection of quality mercruiser parts, marine engines, marine parts, boats parts and accessories, such as Mercuiser engines, exhaust, motors, and other boating supplies and accessories. Find affordable parts for leading brands including Volvo marine parts, Mercury marine parts, Quicksilver...

www.perfprotech.com

 

[ste80]

Would use full flow Gasket

thanks, this is the one that i was noramally using in EFI model right? at least they seams the same of the one that i norlammy used.

what about this component that i never sow on EFI model, shuold i use it (it is a metal resteiction) or should i leve it without it ? thanks

 

[ste80]

this is an ok outline of the differnce between warm and cold manifold systems. on both systems some water is flowing at all times to cool the exhaust regardless of whether the thermostat is open

Raw Water Marine Cooling – The Difference Between Warm Vs Cold Manifolds | PerfProTech.com

Large selection of quality mercruiser parts, marine engines, marine parts, boats parts and accessories, such as Mercuiser engines, exhaust, motors, and other boating supplies and accessories. Find affordable parts for leading brands including Volvo marine parts, Mercury marine parts, Quicksilver...

www.perfprotech.com

thanks so much. i was wander if in EFI model some of the water was going thruought the manifold as well. thanks

 

[alldodge]

I don't know
Hey @Scott Danforth you have an idea what those are?

 

[Scott Danforth]

Not sure what that gasket is for

 

[Scott06]

Those look like restrictor for the exhaust crossover in the intake. Look like they go in the holes in gaskets just to the right of the intake ports with the two Siamesed Intake ports

 

[Scott06]

thanks so much. i was wander if in EFI model some of the water was going thruought the manifold as well. thanks

Both designs water flow through the manifold. warm manifold with separate feed to risers. Water only is supplied to manifold when thermostat is open, cold manifold gets flow all the time.
in the end I think either design works. Thought was for less condensation with warm manifold. I have had boats with both never noticed any difference or had any issue

 

[ste80]

Not sure what that gasket is for

tks;
that gasket are the gasket between heads and intake manifold. in the pack i had this 2 metal restrictions but in the efi if i remember wel it was not any restriction. ( this LX was not mine and i bought already disassembled so i don't know haw it was.

 

[Scott Danforth]

tks;
that gasket are the gasket between heads and intake manifold. in the pack i had this 2 metal restrictions but in the efi if i remember wel it was not any restriction. ( this LX was not mine and i bought already disassembled so i don't know haw it was.

Then it's not needed

 

[Lou C]

Both designs water flow through the manifold. warm manifold with separate feed to risers. Water only is supplied to manifold when thermostat is open, cold manifold gets flow all the time.
in the end I think either design works. Thought was for less condensation with warm manifold. I have had boats with both never noticed any difference or had any issue

My OMC like all OMC/Volvos has the cold set up, I scoped the elbows with an inspection camera this fall and could see that on the starboard side (runs slightly hotter) there was no evidence of condensation, on the port side (runs slightly cooler) there was slight evidence of condensation, but this is just idling on the water hose on a cool day. These manifolds on the outside idle at about 100* and only get to 135* after running on plane, the hottest I ever saw them get was about 145*. No sign of corrosion on valve stems though, when I had the exhaust off to get at the steering actuator a few years back. I think the OMC/Volvo system is a bit simpler, but the Merc warm manifold set up may be better for people who boat in areas with lower water temps.

 

[ste80]

Then it's not needed

sorry for delay in reply yesterday i was all day in the motor trying to find all components and location for all components that i bought i a box
this is the picture of the gasket with this metal part in the position where it should go ( is th only place with that shape so i presume the place where it should go is that.
but really do not uderstand the purpose of this, what is the reason of a restriction over there.

 

[ste80]

My OMC like all OMC/Volvos has the cold set up, I scoped the elbows with an inspection camera this fall and could see that on the starboard side (runs slightly hotter) there was no evidence of condensation, on the port side (runs slightly cooler) there was slight evidence of condensation, but this is just idling on the water hose on a cool day. These manifolds on the outside idle at about 100* and only get to 135* after running on plane, the hottest I ever saw them get was about 145*. No sign of corrosion on valve stems though, when I had the exhaust off to get at the steering actuator a few years back. I think the OMC/Volvo system is a bit simpler, but the Merc warm manifold set up may be better for people who boat in areas with lower water temps.

thanks, when you said worm you mean vesion with 4 pipes only right? whater here in italy dusring summer is between 28-32 degrease, the issue is on the ports when i go back that last area is a river so i have 19- 20 degrease celsius
i think my first motor ( omc had this system but i used it for very short time, than i had the EFI with 4 pipe system and now this.

 

[Lou C]

sorry for delay in reply yesterday i was all day in the motor trying to find all components and location for all components that i bought i a box
this is the picture of the gasket with this metal part in the position where it should go ( is th only place with that shape so i presume the place where it should go is that.
but really do not uderstand the purpose of this, what is the reason of a restriction over there.

Those restrictors are for the exhaust crossover in the intake to warm the base of the carb & auto choke spring. The restriction limits the flow to keep from overheating the carb base….