2015 Motor MerCruiser 4.5L 250hp NO EC - OVERHEATING!

[alldodge]

reading everything again, yes from the crossover when the motor is on, a thin flow of water move from the crossover to the check valves.

There should be a lot of water moving that way

 

[leosmdp]

alldodge I just got home after all day working on the boat removed the crossover / the poppet valve / all the hose cleaned and sadly nothing changed .
the crossover right now it clean as a new and from inside the holes I put some rust remover and cleaned (lot of dark water come out when put water after clean it)
But any ways the temp went out slower but high anyways.
I guess I did everything I could at this point.

Holes inside the motor
Motor without cross and alternator
Crossover cleaning
Poppet valve cleaning and test
I tested the poppet valve with garden hose and water flows from one to the other ok
From the crossover when the motor is on only hot gas travel throw the hoses when is off come water from the manifolds

 

[alldodge]

I guess I did everything I could at this point.

Picked up my grandson today You have done great work, the puzzler for me is why water doesn't move up the hose to the crossover instead of it going down.

 

[leosmdp]

alldodge thanks! enjoy your grandson!!! have a great weekend!.
I will keep thinking about what else could be... may be head gasket at this point. or new manifolds and riser but water moves there without issue.
I saw you have the same motor on the chap 280? but with heat exchange?.. question what are the temp on the mans and riser?

 

[alldodge]

Thanks
My Chap 280 has twin 250 Verado outboards

 

[leosmdp]

Update,
I ended called a mercury mechanic certificated, after connecting the computer he noticed too high pressure in water pressure due to a bad manifolds and riser .5 gph when the normal is around 2. so I ordered today new manifolds and risers (2100 $) ....it hurt. hoping that after this work fine.. I will add a video of the process to help everyone how to change in manifolds and riser in this motor on YouTube when I finally replaced it...
Do you have any post or a way to open and clean the check valves? ( I remember they twist but I dont know if a put a screw driver and make press maybe they broke..)

 

[alldodge]

Don't know of a way to open check valves without breaking them.

Ouch on the cost for the mans

 

[Lou C]

that's why a cat converter equipped inboard is a no sale for me. Not when I have to replace manifolds every 5-7 years. Especially because outboards get a pass on that.

 

[leosmdp]

Update,
I ended called a mercury mechanic certificated, after connecting the computer he noticed too high pressure in water pressure due to a bad manifolds and riser .5 gph when the normal is around 2. so I ordered today new manifolds and risers (2100 $) ....it hurt. hoping that after this work fine.. I will add a video of the process to help everyone how to change in manifolds and riser in this motor on YouTube when I finally replaced it...

that's why a cat converter equipped inboard is a no sale for me. Not when I have to replace manifolds every 5-7 years. Especially because outboards get a pass on that.

next time will be definitely outboard but.. I'm in the learning process of paying the fee here and there for be a newbie..
the question is should I buy a new check valve or use the same old ones...
also, yesterday got an error in the trim sensor so I will try to clean it or hardly remplace it.

 

[alldodge]

I probably reuse the old check valves

 

[alldodge]

If you get CAT's again make sure motor is closed cool, but OB's are the way to go even more so in salt water

 

[Lou C]

Either that or get an older boat last year without cats.
I’m keeping this one as long as I can when the time comes I will just get a reman 4.3. Cheapest way to do boating even though here Id also be better time wise off with an OB, I do know my way around the old Chevy small block. Nothing cheaper/simpler than the SBC….

 

[leosmdp]

Good morning, so yes I bought this as a special deal knowing about this error and the cost to replace parts, but with a huge gap between the price market and what I pay for it. hoping to sell it after enjoying the rest of the summer and keep an eye on OB, future question about which are the best OB motor? price=quality.

 

[Lou C]

Most common appear to be Mercury & Yamaha although Suzuki is gaining ground. See what’s most common in your area…

 

[alldodge]

If you look new or after 2011 all IO have cats. This is main reason I went OB. Also nolonger need to hang upside down to change something.

I stick with Merc because you can find help, no so easy with others

 

[Lou C]

Although here in coastal NY Yamaha is everywhere

 

[Dubed]

Although here in coastal NY Yamaha is everywhere

Yep, in RI and Massachusetts mostly Yamaha and Suzuki is definately on the upswing