MCM 260R Exhaust/Cooling System Questions

[San_Diego_SeaRay]

Engine: 1981 Mercruiser MCM 260 retrofitted w. the MCM 260R Center Rise Manifolds and newer thermostat housing

I'm rebuilding this engine, on the verge of getting it started (may get it started tomorrow) and I plugged a hose into the intake port on the t-stat housing. Water started coming out of the side of the Chevy 350 through a threaded hole mid-length along the block right above the oil pan. On the direct opposite side (starboard) of that threaded hole, there's a little spigot thingy that I guess is a drain ****. Also, water started coming out of a little hole right at the base of the final manifold exhaust outlet, where the "boots" mate w. the riser. I've included a picture pointing to the hole, and another picture showing the hole location better (although you can barely see the hole).

3 questions if I could:

1. On initial start up after a long rebuild and my water jacket is dry, if my thermostat is not open and water is being re-directed to the risers and bypassing filling up the jacket, isn't this going to be a problem? Seems like the engine will be running for a while w/o water to help absorb and dissipate heat.
2. The port side hole probably gets another drain **** just like the starboard side, right? Can I just put a bolt in there w. sealant if I never plan on winterizing the boat?
3. What's the little hole in the riser for? Water is only leaking out of the port side. The starboard side has a hole there too, but it looks like it might be plugged.

Thanks in advance!

- JC

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[Bt Doctur]

Thats never going to work You need wet exaust hose between the arrows. The block drains take a 1/4 ich pipe plug, NOT BOLTS
It is best to pre-fill the motor before firing it for the first time. water must be supplied and water will always exit the exaust manifolds regaedless of thermostst porition

 

[Bondo]

Ayuh,.... Like BD says, you've got mis-matched exhaust parts, the rubber coupler covers the area that's leakin',....

Ya can't fill the block, with a drain missin' either,....
Ya need a 1/4" pipe plug, not a bolt to seal the drain,....

 

[San_Diego_SeaRay]

Ayuh,.... Like BD says, you've got mis-matched exhaust parts, the rubber coupler covers the area that's leakin',....

OK thanks. I should have explained that this is a temporary solution to guide water away from the engine while I try to get the engine started. I still need to buy proper wet exhaust pipe and some elbows so I can hook this up to a Y pipe. But that's down the road. At this point I just want to get the engine started.

Ya can't fill the block, with a drain missin' either,....
Ya need a 1/4" pipe plug, not a bolt to seal the drain,....

Yeah this is a bit of a puzzle. The thermostat isn't open, so shouldn't all water be redirected to the risers and none to the water jacket? But if there's water coming out of the drain **** hole....

 

[Bondo]

OK thanks. I should have explained that this is a temporary solution to guide water away from the engine while I try to get the engine started. I still need to buy proper wet exhaust pipe and some elbows so I can hook this up to a Y pipe. But that's down the road. At this point I just want to get the engine started.



Yeah this is a bit of a puzzle. The thermostat isn't open, so shouldn't all water be redirected to the risers and none to the water jacket? But if there's water coming out of the drain **** hole....

Nope,.... The block will fill with the 1st water available,....

The t-stat stops water from Leavin' the block, not from water gettin' into the block,....

 

[San_Diego_SeaRay]

Nope,.... The block will fill with the 1st water available,....

The t-stat stops water from Leavin' the block, not from water gettin' into the block,....

Ah yes. Now I get it. Thanks again!