Intake ideas to think about

[anzomcik]

I have a 86 merc 90 L6, which i have another metal motor cover. I am pretty good with my hands and i was wondering if anyone had made or tried to make intake tube that extend out of the motor covers so the motor breaths fresh cooler air, that would be forced in the motor by the movement of the boat (ram air)

just wanted to know if i was wasting my time thinking of things like this. Thanks

 

[Laddies]

Re: Intake ideas to think about

Most of these setups are prone to water injection which is fatal to a 2 stroke engine

 

[DutchMerc]

Re: Intake ideas to think about

I wonder if the modification would make an improvement on performance.. You have to extend the inlet, instal a good filter to make sure there is nothing sucked into the system other then clean air (you don't want any water-spray into the inlet) This will cause more resistance then you need. But maybe it's worth a try, let us know how you're doing... Photo's maybe??

 

[anzomcik]

Re: Intake ideas to think about

Has anyone seen or tried this? To me it looks like there is a good chance of improvment in motor preformance. I guess one quick way of seeing if there is anything reason to my thinking is try running the motor with out the hood on. That way the motor will have fresh air, and see if things improve.

 

[Chinewalker]

Re: Intake ideas to think about

You're not going near fast enough to have any sort of ram air effect. Many motors actually perform worse when you open things up in front of the carbs, as the plates often act as a tuner of sorts. There is a standing wave in front of the carbs, in time with whatever RPM the motor is running at. That wave tends to "bounce" a bit more air/fuel into the carbs when running. Similar idea to tuning the exhaust with stinger pipes and whatnot. You use the sonic waves to push more fuel/air in and scavenge more exhaust/less fuel out.

Also, most motors are jetted to whatever air restrictions are in place and simply running them with covers removed can actually cause damage to the motor.

If you want to improve performance, focus your energies on set-up and propeller work before trying to modify the motor. Most rigs will benefit greatly from time spent in those areas...

- Scott

 

[mthieme]

Re: Intake ideas to think about

True, I've seen bigger motors that ran like crap while the intake baffle was off.
While your thinking is sound, you won't get any bang for the buck as the rest of the breathing will be unchanged.
I have a jet boat that sucks a little spray down the carb will no effect, but it's a 454 Chevy...I'm just cleaning out a little carbon. I'd be afraid if my stock outboard did that though.
How about modifying the cowl with a little scoop on either side or the top?
It's fairly airtight and any water will seep out the bottom.