Optimax fuel delivery issues???

[PCDOC]

2012 Pro XS 175 with 130 hours.

Fell on it's face at WOT and bogged out. Still ran, but I could not get on plane before it would bog. Shut it down and after 1/2 hr I could get WOT for maybe 5 seconds then it bogged again. This repeated all day. No beep codes or any alarms.

Later in the day it was hard to start also.

I pulled the low pressure pump and am only getting 4 psi. This is sitting on the bench just pushing air (not sure if that makes a difference). I think it is supposed to be pushing 6-9 psi. Local Merc mechanic said they either work or they don't. Obviously he has the experience, but it is not in spec.

Guessing it wouldn't run at all if the high pressure pump was shot, but I haven't pulled the vapor canister off yet.

Anybody have ideas???

Thanks

[Burr]

I'll only mention it, because it's a low cost fix if it's an issue - is the tank breather open?

Ya, happened to me....

[PCDOC]

Haven't checked that yet, but I did unscrew the filler cap several times when it was acting up to see if it had a vacuum in the tank.


Both pumps cycle when the key is turned on and the high pressure pump has pressure in the lines. Haven't checked the psi yet, but it had pressure when I removed the hose from the outlet side of the high pressure pump.

[PCDOC]

Just checked the tank breather and I can blow through it.

[Custom Eyes]

Could be the infamous tracker valve diaphragm. It's job is to help regulate fuel pressure and symptoms can be very similar to yours. My engine would bog down pretty quickly after any significant increase in throttle and would "moan" if I tried to go to WOT.

[PCDOC]

Assuming you are meaning something specific to tracker boats?? Or am I way off base?

[Custom Eyes]

Originally Posted by PCDOC

Assuming you are meaning something specific to tracker boats?? Or am I way off base?

That's what I thought when I first heard the name of it. lol No, it's a valve/diaphragm located on the starboard side fuel rail. VERY common cause of issues like yours. They have new/updated diaphragms. New/updated ones are purple, old style are that green-aqua color.

https://www.walleyecentral.com/forums...cker+diaphragm

http://www.airinjectors.com/trackervalve03.jpg

[PCDOC]

Thanks for the tip. Any way to figure out if the tracker diaphragm is bad or just replace and hope???

On a side note. Any idea how much fuel should be coming out of the vacuum driven pump when cranking? I held a bucket under the hose while it was turning over and gas came out, but not a large volume. Guessing it pumps more when it actually fires????

[06x6spdGTO]

If the Tracker valve is shot the boat will surge at idle, you should also be able to push on the air side schrader valve and smell or see gas.

If this only does it during the heat of the day I have a high suspicion of vapor locking.

[PCDOC]

It has never surged or had any trouble at idle. This issue started at 7:34 am, so it was not hot out. I know the time because it was 4 minutes after the shotgun start of a tournament we were in (long 8 hrs with only a kicker)

I did notice the hole shot wasn't as good as normal that morning. That motor on a tin boat and it normally rockets out of the hole.