2.5 200 motors over heating. Please help out of ideas

[demag67]

Okay so here is the rundown the power heads are 2.5 liter 200s they used to be on 25 inch mid sections for 2.5 liters, somebody else had changed the 2 25 inch mid sections out for set of 2. 2.4 200 20 inch mid sections. originally the motors had the poppet valves deleted and plugged off so we hooked them up and we had low water pressure and the engines were running Hot. Also keep in mind this problem all started around midsection change, previously engine temp and water pressure was good. so we were changed the poppet valves and the water pumps and the thermostats and we still have low water pressure and the motors were still running hot. this is my buddies boat so it came to me broken or not correct and have I have been trying to figure out what is going on here and just can't come up with any other ideas we plugged up the hose to the poppet valve and plugged them off and we have high water pressure 20 pounds at 5000 RPMs but then the motors were overheating any help would be great

[tlwjkw]

did ya keep tha adapters with tha 2.5's?... if used tha 2.4 stuff, were tha 2.4 adapters one piece or two?

guess ya know for sure what shape tha pumps are in?

[DropTop5.0]

Two-piece adapters were used. 2.4 on the bottom and 2.5 on the top. Thank you for any help you can give.

[tlwjkw]

Two-piece adapters were used. 2.4 on the bottom and 2.5 on the top. Thank you for any help you can give.

???... what was used between tha down housin' and power head? those are what i'm referring to as one or two piece adapters... they are between tha power head and down housin'.... those are exhaust adapter plates/plate, either one or two piece..... either 2.4 or 2.5... if they are 2 piece, both plates have ta be one or tha other... can't mix and match.....

[DropTop5.0]

Sorry if I'm not using terminology correct.

This is my 25" mid and this plate is still attached.

[DropTop5.0]

I was told by the person who did the work that the lower piece in this pic is 2.4 and the upper is 2.5.
He said it shouldn't make a difference. I believe I also read somewhere that it was fine to do that as well. However I am a novice and do not have any experience of building motors.

[tlwjkw]

your missing "half" of tha exhaust adapter plate.

[tlwjkw]

forget tha power head and tha down housing for now.... concentrate on tha 2 piece adapter plate... thats tha TWO parts that sandwich tha motor mounts... 2 piece (like yours that is only half there) exhaust adapter plate has 2 parts that have to match whether its 2.4 or 2.5 but still has ta be "both pieces"......matching 2.4 pieces or matching 2.5 pieces they can't interchange no mater what!.. power head has nothing ta do with those two parts as for that goes right now... at least till ya get tha adapter parts squared away.....

probably what your hearin' is tha a 2.5 will work on a 2.4 mid... that is correct but it has to include "BOTH ADAPTER PIECES" for tha 2.4... tha 2.4 and 2.5 adapter pieces can't be mixed period.

[DropTop5.0]

Ok. I'll need to figure something out. Thank you.

[tlwjkw]

no... in post 5....

but what you are sayin' that in post 6 showin' "both halves" is that tha top half is a 2.5 piece and bottom half is 2.4 piece if i read it right... thats a no-no and will never cool right......

[demag67]

Should we keep them both 2.4 or put both 2.5 if we can get them. Someone else put his power heads on the 20 mids. Im not sure why he didnt just use both plates from the 2.5

[transomstand]

Use 2.5 if you can get them

[demag67]

Were gonna have to find them if it will fix the problem

[DropTop5.0]

Putting matching 2.5 plates on tomorrow. Hoping for the best.

[superboattwin250]

You cannot mismatch plates. Also the gaskets between a 2.4 and 2.5 are different. Run the correct upper and lower 2.5 plate with a 2.5 gasket. Big problems if you mix and match. I did this once before and I was going crazy