175 Opti Cuts out, low fuel/air pressures

[thormx11]

I have a 2006 opti 175 that I am trying trying to figure out. It has no problem starting or idling, although it does have a random miss/rough idle at times that you can feel. The boat had been sitting a long time when I got it and the electric pumps were not working. I replaced all 3 of the fuel pumps, along with the hose/bulb from the tank to the engine. It fired right up and ran great for the first few weeks until it randomly died and would not crank again. I got it back to the house and replaced the plugs, high pressure fuel pump again (I broke it taking the VST apart) and the tracker valve.

The engine started right back up after. I took it to the lake and thought everything was good until trying to get it up on plane. When pushing it above 3k rpms it would cut out and die unless I backed the throttle back to neutral again. I have the bluetooth smartcraft hookup for my phone and it doesn't show any trouble codes when this happens. Its like it runs out of fuel in the VST and has to fill back up before trying to take off again.

Today I bought a liquid filled pressure gauge and checked my fuel/air and the fuel was showing 84-86 psi and air was showing 74-76 psi, both while idling. I believe it is supposed to have 90 psi for the fuel and 80 psi for the air.

 

[vroom ZOOM]

I have a 2006 opti 175 that I am trying trying to figure out. It has no problem starting or idling, although it does have a random miss/rough idle at times that you can feel. The boat had been sitting a long time when I got it and the electric pumps were not working. I replaced all 3 of the fuel pumps, along with the hose/bulb from the tank to the engine. It fired right up and ran great for the first few weeks until it randomly died and would not crank again. I got it back to the house and replaced the plugs, high pressure fuel pump again (I broke it taking the VST apart) and the tracker valve.

The engine started right back up after. I took it to the lake and thought everything was good until trying to get it up on plane. When pushing it above 3k rpms it would cut out and die unless I backed the throttle back to neutral again. I have the bluetooth smartcraft hookup for my phone and it doesn't show any trouble codes when this happens. Its like it runs out of fuel in the VST and has to fill back up before trying to take off again.

Today I bought a liquid filled pressure gauge and checked my fuel/air and the fuel was showing 84-86 psi and air was showing 74-76 psi, both while idling. I believe it is supposed to have 90 psi for the fuel and 80 psi for the air.

that fuel pressure is for the high pressure side. Use a chunk of clear hose to check for any air bubbles, and check the low pressure pump.

 

[thormx11]

that fuel pressure is for the high pressure side. Use a chunk of clear hose to check for any air bubbles, and check the low pressure pump.

Where to use the clear hose? From the tank to the engine? The low pressure pump cycles when the key is turned on, but that's as far as I've checked it. I removed the VST again today to check everything over and the fuel inside was very varnished. The fuel tank & VST was drained before the boat sat for ~10 years. The tank was clean and I originally removed the VST to clean it & replace the fuel pumps and everything was clean then. Today when removed it the fuel from the tank was clean (it was filled up on July 4th) but when I removed the VST the fuel I drained out of it was very nasty. I cleaned everything out again and put it back together. I am waiting on a new fuel/water separator filter to come tomorrow to finish putting it back together. I am also going to rebuild the pulse pump with a Mercury kit I have while I have everything apart.

 

[Faztbullet]

Inspect tracker valve..most likely the diaphragm is degraded

 

[vroom ZOOM]

I have a 2006 opti 175 that I am trying trying to figure out. It has no problem starting or idling, although it does have a random miss/rough idle at times that you can feel. The boat had been sitting a long time when I got it and the electric pumps were not working. I replaced all 3 of the fuel pumps, along with the hose/bulb from the tank to the engine. It fired right up and ran great for the first few weeks until it randomly died and would not crank again. I got it back to the house and replaced the plugs, high pressure fuel pump again (I broke it taking the VST apart) and the tracker valve.

The engine started right back up after. I took it to the lake and thought everything was good until trying to get it up on plane. When pushing it above 3k rpms it would cut out and die unless I backed the throttle back to neutral again. I have the bluetooth smartcraft hookup for my phone and it doesn't show any trouble codes when this happens. Its like it runs out of fuel in the VST and has to fill back up before trying to take off again.

Today I bought a liquid filled pressure gauge and checked my fuel/air and the fuel was showing 84-86 psi and air was showing 74-76 psi, both while idling. I believe it is supposed to have 90 psi for the fuel and 80 psi for the air.

also need to check fuel and air pressure when its acting up at higher rpm, under load, idle doesn't tell you anything.

 

[thormx11]

I believe the gauge may have been off. I checked the air side with a tire gauge and it was right at 80 psi idling. I took the boat to the lake this weekend and on Friday when I put it in the water I took it around the bay (no further than a mile) at different speeds and it ran perfect. I brought the boat back to the slip for the night and Saturday when we went out it cruised perfectly at around 35-3800 rpms. We only went probably ~3 miles up the lake and anchored for the day. A few hours later a storm started rolling in and we were trying to beat it back to the marina. We were cruising around 4500 rpms on the way back and it was running perfect until we got back to the marina. It never died but it started to cut out like before and I backed the throttle down. I never got to really run it again or check anything before we loaded it back on the trailer.

I am still thinking it is a fuel supply issue. I removed the pickup from the tank and there is no anti-siphon valve or screen in the pickup.