PCU 2.5 260 hp help

[fastercat]

will the new pcu make them start better idle better and not load up on idle???????????????????.i can only get them to idle 700rpm i wood like to see 550rpm to shift them with no clunk???????.I HAVE NEW POWER HEADS WITH 1992 BOLT ONS. but i have gone threw every thing sent out injectors new fule pumps filters re plumbed fule lines return to tank.all electrics have been checked and meet all spec's.i am sick of it stalling out when i am dooking or even when pulling up to a frend.i have read some things on this but i need first hand info from others that run this set up the pros and cons of the pcu. :confused: :confused:

[Raceman]

I don't think there are any cons. In my case it's the best outboard bolt on I ever bought. Mine never loaded up at idle. I only ran it with a Speedmaster, so it was always in gear, so I don't know firsthand about shift/idle speed, but I'd guess Tony can make it do most anything you want from it.

[Scream And Fly]

From my experience:


Pros:

Your engine will idle much better
You'll gain more power all the way up the powerband
Gains on top end too, even for completely stock engines
Improved fuel economy
Versatility like you never imagined

Cons:

You'll constantly wonder why you didn't get one sooner

[stvhelm]

Not for nothing, but If I get mine to idle that low it dont pump water that good. I found I had to richen up the idle alot on my pcu to idle nice and start easy. I would invest in the newer style horn and ecu bracket from like a 95 or newer 260. they have an adjustment screw for the butterfly so you can adjust the air intake together with the idle timing for the perfect combo. I have my idle set high about 1100rpms and I just stop shift and start around the dock. It starts in gear immediately with a touch of the key after the initial cold start up.

[Markus]

My engine idles to 600 rpm with an analog ECU as well as with a PCU. I have not tried to go lower.

Idle with the PCU is more stable, though, especially when the engine is cold.

[THE FAST ONE]

will the new pcu make them start better idle better and not load up on idle???????????????????.i can only get them to idle 700rpm i wood like to see 550rpm to shift them with no clunk???????.I HAVE NEW POWER HEADS WITH 1992 BOLT ONS. but i have gone threw every thing sent out injectors new fule pumps filters re plumbed fule lines return to tank.all electrics have been checked and meet all spec's.i am sick of it stalling out when i am dooking or even when pulling up to a frend.i have read some things on this but i need first hand info from others that run this set up the pros and cons of the pcu. :confused: :confused: THAT IS AWFULLY LOW IDLE FOR ANY 260,550RPMS TACH MUST BE SCREWED UP.PCU OR ECU,HAVE TO SEE IT TO BELIEVE IT.

[Trikki1010]

:confused:

@ 500 RPM's w/ a taller prop on there,,,,

Wouldn't it stall anyways :rolleyes:

[stvhelm]

The shift clunk you get is from tall pitch props. The bigger pitch prop you have harder it will clunk. Try a15-17p and you'll see what i mean. Some motors have a shift interupt switch for the ignition so you can shift without a clunk. thats something you might want to consider adding to yours

[steve]

Why aren't you guys starting the motors in gear to save that poor little clutch dog? Just connect your 2 yellow w/ red stripe wires together in the shifter harness. Also the 260 or any motor will load up more if you don't have enough exhaust relief at idle. Try trimming the motor up a ways and see if it doesn't start to lean out a bit. Watch the tach and the smoke. Trim down and see if it starts loading up again. If so, then you need better above water relief.

[fastercat]

thanks for all the all the input i have the safty by pas so i can start in gear but it is not much fun to dock it that way.i run 15-30 clever prop i will not go down on pitch due to speed and rpm but i think you right about big pitch prop dont help with the clunk :eek: .DO I HAVE TO BE A BRANE SURGEN TO SET THE RIGHT SETTINGS WITH THE PCU.can you mess up and set it so you may blow motor?????????. :confused: .i have been in to outboards since the 70s but this is the first time with these 2.5 260 efi motors never had any of this isues with all my other merc's.my last boat 21 skater with 300pm was great in these regards.does every one mount the PCU where you can ajust it going down the lake or mount it in back of boat?????????. :confused: i run a lot of runs that take you in no wake zone for long time and it loads up motor will this cure that :confused:

[steve]

If you use a very long vacuum line you may have problems getting it to run right in my experience. Even the type of hose effects it. This is because the signal to the MAP sensor is delayed and air compresses, stretches.
I prefer inside the boat towards the rear of the boat, hard vacuum line to the motor that connects to a short pc of tygon from the PCU itself. If you follow the directions Tony gives and you are certain of what curve you have in the PCU for starters, you should have no problem setting it up.

[fastercat]

looks like tony will supply 6' or12' wiring and hose to mount up front it must be ok??????????. :confused:

[stvhelm]

I hope you dont think by switching to a pcu you're gonna make it idle lower. All the pcu does is control fuel delivery. Yes its adjustable, but only the air and timing will control your idle rpms. The pcu adjusts itself according to the amount of vacuum it reads, and you can control how much of an adjustment the pcu makes. most people including myself have mounted the pcu in the back of the boat and just run the external adjustment knob (steamwheel) by the driver seat.

As far as your poor idle, loading up, and stalling goes, it's because it's too rich and you have not enough idle timing. some people make the mistake by opening up the butterfly to give more air and retard the idle timing to bring rpms back down to normal. Well opening up the air does NOT make it leaner. It makes it richer because your ecu is monitoring the vacuum and when vacuum is decreased by an open butterfly then fuel is increased. The right thing to do to make it leaner at idle is reduce the amount of air it gets and increase the idle timing. That needs to be properly adjusted for any ecu. It will start and idle much nicer too.
Notes:
The idle timing adjustment is the thin screw in the middle on your throttle arm.
The air adjustment at idle depends on which horn you have. The older ones have holes in the butterfly which can be plugged and opened and newer ones have a screw on the side.
When you have your engine starting and idleing good then add the pcu. doing it before will complicate the hell out of things.

I just want to add another thought. The syptoms your having like poor idle, stalling, and loading up... If the motor is loading up it would be smoking quite a bit. Now if the motor is not smoking its very possible that is not loading up but rather starving for fuel. this would also give you poor idle and stalling. Its very possible that it could be the complete opposite with the idle timing and air intake adjustments. The smoke and burning feeling in your eyes would indicate rich and loading up.

[fastercat]

ha stvhelm it sounds like you are the man to talk to it makes sense i pluged one hole in butterfly and it did idle better.but it wanted to stall when taking off if i hit enrichener it wood go.i set timing to merc spec's. but doesn't meen i was lean so i took out screw.how can i get the motor to run in no wake zone????????.

[Trikki1010]

Just goose it once in a piece ;)

[steve]

Yes, you can mount it up front . What I am saying is that its more sensitive to the type hose you use when you run it longer distances. Ask Tony, he'll tell you the same. A hard line is better. The sensitivity feature helps but the harder hose will work much better on longer runs.

[stvhelm]

If you pulled out the little screw on the timing arm then your idle timing is way too advanced and the motor is idleing lean. put that screw back in and back off the idle timing and unplug the hole in the butterfly. you have to do them both or it wont idle right.

[steve]

You will not be disappointed with the PCU once you have everything dialed in. Try what I mentioned above with trimming the motor higher to see if its actually choking itself at idle. A lot of rigs will do that . Get that fixed first if its an issue, then dial in the timing and air. Usually we like a little more idle timing then the Merc spec calls for. Also if you have a slide on your throttle crank for the butterfly, it may help to adjust it a few turns. You may also want to check your MAP hose fitting on the airhorn and be sure its open and see which size orfice you have. The digital box uses a smaller orfice then the analog does. Give Tony a call if you have any problems adjusting the PCU, he's always there to help.

[fastercat]

THANKS FOR ALL THE INFO VERY HELPFULL i will keep up dated how it works in spring had to put to sleep for winter. :(

[nelsoncat]

If I put a PCU on my 260, will my digital box work on my 220 lazer?

Craig

[steve]

It will need recurved though and you will not have a cold start/ hot circuit for water temp. When you run stats, they run better with the water temp circuit when warm. It will run, but not correctly.