Still Can't get the 225 EFI to pull over a 24P prop

**ttmott** · 08-28-2015, 04:53 PM

I’ve been fighting this problem for three months now and can’t seem to get a grip on what is causing it…
Boat is a Gambler 206SS with a Mercury 225 EFI
The motor will not pull the hull on plane with anything over a 23P prop. It only will rev to around 2400 RPM and plow the hull. It doesn’t really sound “healthy” when it’s stalled at 2400 but not missing, rather sounds too rich. I tried with the jack plate up and down, engine in and out and all of the combinations inbetween……

Here is what I have done to troubleshoot:

TPS is set dead on to spec. Checked multiple times…
Stator is in spec on all coils, albeit, two are on the low side.
Ign. coils all check OK.
Compression are all excellent and within 5 PSI of each other
Fuel pressure at key on and idle is within spec and with key turned off stays up and stable.
I raised the jack plate up to get the idle exhaust relief port out of the water.
This vapor separator has no return fuel screen so I assume the pressure regulator is properly controlling.
The plugs look wet after trying a launch
Engine starts right up and settles to a very good idle.
I’ve tried a Bravo 24P, Laser 25P and the one on now a Tempest Plus 26P without luck
The props are tight to the foot with minimal gap
The previous motor I had was an Evenrude Looper with a 28P Chopper and it ran great.

So the only open item I haven’t looked at yet are the reeds – Can they be a contributor to the issue? Any suggesting are greatly appreciated!
Here is a picture of the setup:

**ttmott** · 08-28-2015, 05:02 PM

Oh, and with a 17P prop the motor will launch the hull completely out of the water then instantly bang the rev limiter.
Another Pic...

**half fast** · 08-28-2015, 05:03 PM

Are running champion QL77cc plugs or something else.How is the top end speed ? or will it get there at all hf...

**ttmott** · 08-28-2015, 05:08 PM

Yes QL77cc only.
I wish I knew the top speed but with these props will not even come out of the hole....
The Evenrude pulled it to 88 GPS

**eli** · 08-28-2015, 05:12 PM

something just don't add up you say 17 pitch will launch hard and bang limiter ,
think its time for leak down test might answer all your questions .
you can have good compression with bad leakdown numbers .

**ttmott** · 08-28-2015, 05:15 PM

Yes - It simply doesn't seem to add up.... The motor just seems to be very weak up to some RPM; like 3500 or so. Reeds???

**TEXAS20225** · 08-28-2015, 07:11 PM

what year is it

**ttmott** · 08-28-2015, 07:30 PM

2000
New Power Head in 2012

**TEXAS20225** · 08-28-2015, 07:33 PM

so its two brain model motor ignition and fuel boxs

**ttmott** · 08-28-2015, 07:34 PM

2000
New Power Head in 2012
Also, when I installed the solid motor mounts and SS steering arm I cleaned up the exhaust holes above the tuner. Problem was happening before that work however and cleaning up the exhaust holes had no improvement...

**ttmott** · 08-28-2015, 07:35 PM

Yes it is a two brain

**vnemous** · 08-28-2015, 09:34 PM

Have you tried a prop with that pitch that has vent holes

**ttmott** · 08-29-2015, 06:04 AM

All of the props have the vents. They were not opened. Regardless, the motor should spin up all of these props with closed or open vents, right? The vents should be used as a tuning feature rather than to get the prop to work I would think.

seems to me it's something in the motor; Eli (earlier post) thinks a leak down is in order which I'm going to have done. And something of a dual computer comment that I don't know where that is going. I've queried if the reeds can have anything to do with this but no comment back yet.

**ttmott** · 09-21-2015, 04:33 PM

I wanted to revive this to update for others benefit.
took the boat to the mechanic and they say the motor is tight and in perfect shape. They did a slight adjustment to the TPS to up the bottom end but that is it. They went through the props and discussed the vents; recommended to remove the vents on the 26" Tempest Plus and run it. To my complete surprise with all three vent plugs removed the motor blew the prop out, and wouldn't come over on plane, amazing... Plugs in motor won't pull the boat out of the hole and plugs out the motor blows out the prop.. So, one plug back in and the boat launches very hard and sets plane perfect. Water was too rough to see if one plug will hit the rev limiter so more testing. Amazing what those three 5/8 inch holes will do...

**TEXAS20225** · 09-21-2015, 09:04 PM

you wont believe how much trouble ive had with some of my customers who i rebuild thier motors or sell them a new one when i tell them they have the prop all screwed up they get real huffy till i fix it for them and then they have a whole mouth full of well ill be it never took off/ ran like that before

you never know till you get some help

some real help Good luck mister sounds like your fixing to get smiley