Looking to have a 2.4 merc more power from 5500-7000?

[faztbullet]

This is the odd ball motor that runs the 2.5 head. I took the chamber down from 42cc to 35cc. Getting a true compression number is hard as there are bleed off ports on these cylinders

Only the 91 carb 2.5 200 engine had idle relief. The EFI did not

I would check port height to ensure its a 200 and not a 175....

[wrechin2]

That year check bore size.

[TEXAS20225]

ive owned two of these motors one i got from james the other james whittled on it so much it much be a 300 drag by now it was as 90 model by stamping but a seven petal with no idel reliefs by still had 2.5 pistons not 2.4 hower some2.4 had sthat looked like 2.5 with pins in them best way to put it all asleep is pull a head measure the hole no more well once upon a time then it is what it is after measureing it

[coffeeguy]

I pulled the head when I got it because of the confusion. It is a 2.4 bore, idle reliefs are blocked off with factory caps. As stated earlier it took 2.5 heads, efi. When I look up gasket kits, they come up as being only for the 91 175/200 with no head gaskets provided , but cross referencing to other 2.5s of that era and it is the same pn.

[TEXAS20225]

factory cap in idle relief slots is a first for me wonder how that factory notch plug in the sleeve is secured in im betting its a 175

[W2F a V-King]

It is a 2.4 bore, idle reliefs are blocked off with factory caps.

Would you mind taking a picture and posting it please? I am new to the 2.5 motors ( have 2 now) and am curious to see this.

Thank You,

James

[FORBESAUTO]

Must be mistaken what idle reliefs are and something else is capped off? I hope

[W2F a V-King]

Here is a picture of an exhaust relief...it's the slot cut into the exhaust port.

I was curious about the cap because this sleeve is in my PM 225 #6 hole....and it doesn't belong there ( long story... ). The other 5 are as built by Mercury.

James

[coffeeguy]

I was wrong. I meant the bleeder ports on the outside of block

[FORBESAUTO]

Happens to all us. I figured you was looking at something else thinking it was the reliefs. While you had head off did you notice if it had the notches above exhaust ports? It would have been great if you would have had something to fill the reliefs though lol! Good luck with your mission. Listen to James Perry, he knows what he is talking about and can steer you in the right direction. And Is a super guy. But remember that each set up, boat/engine combination is different and what works on one doesn't always work on another. This is why there is always diagreement over certain topics. Gather as much information as you can. But when it's all said done it's up to you to experiment and try different things to see what works for your set up. Most of the tricks are not always fully freely given lol.

[coffeeguy]

I will try to get pictures in the next week.

[Krazymaan]

Good News... Its Next Week.

[coffeeguy]

Power head off, but not on the bench. (Been working everyday). It is the 175 block (884- 9764 under cylinder 5).

[wrechin2]

If it is a fat block 2.4 I would suggest remove the sleeves and number them so they go back in the same holes I then cut the one finger port up to the top of the port from the bottom. I then cut the bottom of the booster to the rod slot. This give a direct flow for the 2 ports and increase fuel transfer as they don't have to fight the moving piston to pass through. This is very similar to a 2.5 which is way better technology. This is similar to when i "TUBE" a engine but there is enough material that it can be done internally. I also include a finial pic of this one as the exhaust chest was also done. This was done before I done them using a CNC program. This engine was a 175 and on a 361 ranger. It picked up nearly 12 MPH on top after the mods and performed from the hole shot to WOT.

[wrechin2]

Here is pics of my Bridgeport I tubed which woke it up!