crmax

did mine had it ran fine then it wouldnt ggggget over 2900 rpms found the fuel pump went bad, and yes mine makes the noise but not badIm running thru hull, k&n and the trimed gasket what mph and rpms did anyone notice and did you check your plugs to see if your lean now?

turbo2256

After a few outings ... ran out stored fuel.... installed the Jacobs Omni pack from my other boat and just regapped the old plugs ..... they looked rich if anything. I am going to see if they clean up.

JS232

SO guys?

Finally... What's the issue ?

Let's continue that debate... Is it a good thing to cut that gasket??? I am very curious....

JS232

NO BODY?????

turbo2256

It doesn't seem to make a difference one can feel in the real world of varying conditions. It does make a difference that can be heard. Others might think you have some boost..... As I stated before the mismatch is probably there just to reduce the whistle.
I design intake manifolds as well as any other part on an engine and what we call "fingers" in the inlet are incorperated in some designs to reduce NVH.

JS232

Thanks.

So You guys who own the 7.4 MPI as I do... (Mine is a 2001)

Mine is stock-stock no gadgets installed- no K&N no blablabla...

The only thing I have is direct Tru-hull exaust (no mufflers)

Is there any little things I can do to increase anything?

I've read that it's not worth the money to put tousands of dollars on those 7.4.

Any suggestions, tips that have been tested with little succes?

I tought about taking the air outside of the engine compartment.
With some kind of fan. (The air is very hot inside the engine compartment !) It's like a stove in there. Shure, most be carfull for water. Maybe it would be good to take the air in the sides near the bolster seats (there is no water going there). Lets say that the air is 25 degrees cooler, then it would be a 2% increase in power. 310 * 2.5% = 7.75 HP for under 100 $... It could be a beginning...

JS232

Also...

Considering that an engine is a air pump air considering that it sucks the air : If I install a powerfull fan, let's say a 700-800 CFM fan with reducers that would push a powerfull blow directly in front of the flame arrestor... (At wot only).

My thingking is if you are sucking air with a straw and someone blows at the other end of that straw... It would be easier for you sucking more air....

What do you think about that?

robyw1

I brought this up again because I trimmed my gasket and it did seem like it spanks the rev limiter a little harder. Has anyone tried this with any MPH gains? Just curious

Roby

Pat McPherson

Hey Roby,
What is the rev limiter set at?
I normally run a 26p 4400rpm at WOT.
I tried a 24p and got 4600rpm.
-2mph with the smaller prop.

robyw1

Mine starts poping out at 4800. However it is supposed to be 4600 I believe. My tach is probably a little high. I'm running a 25p Mirage plus at 4800. according to my tach