5.7L Engine cuts out/boggs during initial acceleration

[bhunt_34]

I bought a 2007 22ve last weekend and took it out on the lake today for the first time. It ran great for about 2 hours and then we trailered it for a little while. When we put it back on the water, it started fine, but when we started to accelerate the engine started bogging down and cutting out at about 2,000rpm. I put it back in neutral and it idold sporadically for a couple of seconds and then evened out. I then started to accelerate and it did the same thing. Bogged downs and lost power. I then tried to accelerate very slowly and it finally got up to speed and operated at full throttle. I didn't have anymore problems until I shut the engine down for a little while and then cranked back up to start going again. Same thing happened as before but with much worse idol. It only does it during the initial acceleration after start up and then runs fine. The motor has 560hrs on it and is the 340hp 5.7L. As a side note, I test drove the boat before I bought it and it ran fine. I added about 20gal of gas before I took it out today and added Stabil marine fuel stabilizer to the tank. I filled my truck up at the exact same pump as the boat and have had no issues with my truck. I think this eliminates water in the gas. Any advice is greatly appreciated!

[JCP]

A miss when accelerating can often be a secondary ignition problem. Do you know the age of the distributor cap, rotor, plugs, plug wires?

[bhunt_34]

According to the dealer, they did all maintenance on the boat from the time it was new and all that was ever replaced was the impeller and steering cable so I'm guessing everything is original. I can take a closer look later on in the week. I'm also going to call the dealer on Tuesday to see if I can get more info.

As an update, I took the boat out this morning and it ran great. It seems to only have the loss of power after the engine has been ran hard and then shut down for an hour or so and cranked back up. People seem to have had the same issue that I'm describing in other threads and think it's vapor lock in the fuel system. Thoughts?

[JCP]

Running good cold and only running bad after a hot restart does sound like vapor lock. If you have access to non alcohol gas, top off the tank and see if that makes a difference. When you got gas, did you buy a major brand?

[lee]

Still look under the distributor cap, might be full of corrosion.

[rhoadsdj]

I had this same problem at the beginning of the year and it looks like it was indeed vapor lock due to either bad gas, or from running the winter blend the Marina was still using when I filled up in March.

On the next tank of gas the problem went away totally and has never been back.

[bhunt_34]

JCP - I filled up at Sunoco. Would topping off with premium maybe help?
lee- I'll check it out
Rhoadsdj - Thanks for the info. Maybe that's all I need to do is run this tank out and fill up with fresh.

[ericinmich]

Getting a winter blend of fuel (higher RVP, reed vapor pressure, which "boils" off at lower temperature) may be your issue.

I'd top off at a different gas station, one that is very busy...

Premium or not won't matter.

[JCP]

Agree with ericinmich. Also sometimes premium can vapor lock worse, some brands use more alcohol to raise the octane rating versus regular.

[bhunt_34]

Thanks for all the help everyone. I'll get this tank ran down more and fill up at a different station. I'll also check for corrosion. I'll post what I figure out in case anyone else has the same issue.

[CDAWaves]

bhunt - did you ever figure out what your problem was?

I have an 05 24v with MP 340 with similar hours and am having similar problems. The boat runs fine and then randomly the engine will start to stutter and loose power. When I back off the throttle to idle it will idle like normal. After letting it idle a few minutes I powered up and it ran fine at all RPM all the way to full throttle and back down to cruising speed. The issue didn't return that day. A couple of days later it happened again. I don't think it's vapor lock as it's not happening after running the engine hard and it's not after shutting down the engine.

Any ideas? Secondary ignition (Cap, rotor, plugs and wires) wouldn't cause an intermittent problem like this would it?

[jtcrawford1976]

bhunt_34 or CDAWaves

Have either of you figured this out? My boat is doing the exact same thing.

[ChrisSnow]

Sounds fuel pressure related. Get a gauge and hook it up onto the schrader port on top.

Sent from my HTC 10 using Tapatalk

[CDAWaves]

I replace the distributor cap and rotor and it's running like a champ. The inside of the cap was corroded.

[jtcrawford1976]

Thanks, I'll check mine out.