07 21 LSV Sunscape 340 Monsoon

[Sparky450]

I need a little trouble shooting help. I have searched and can not find anything

Last year I noticed full RPM could not be reached. Just down a little bit. Just during the last 2 trips last year.

Put fresh fuel in last weekend and now she will not turn over 4700 rpm.  And I actually have the stock 381 on her right now. Used to pull 5200-5400 with this prop.

It is not throwing any codes. Just acts like the throttle is not pushed all the way down. I did change the fuel filter about 50 hrs ago. I really don't think the filter is the problem. 

However it will definitely get changed first with how easy it is

I guess I should also mention that it has 830 hrs. However, We do not sack out, surf and wake board all the time. Probably less than 100 hrs moderately sacked out 

Most of those hours are pleasure lunch/dinner cruises.

So getting to the questions where would you guys start after the fuel filter. 

And where is the fuel pump on this engine to check the screen,(if it has a screen at the pump)

Thanks

[WAwinegrapes]

new cap, rotor for sure, maybe new wires. and when were the plugs last changed?

 

and like you said, new fuel filter!

Edited March 4, 2017 by WAwinegrapes

[robbennett]

How does the boat run? Is it rough at an idle? Anything else seem out of whack with it? 

The only time I had A similar issue was when the distributor cap had some corrosion in it. Started to have a dead cylinder or two throughout the powerband. Ran to Orielly real quick and was back on the water within the hour. 

I'd also check out and make sure your battery terminals and connections are all nice and tight and clean. That will cause all kinds of weird gremlins to pop up. Having 830 hours there should be nothing major wrong with the engine unless something has happened to it. 

[Sparky450]

53 minutes ago, WAwinegrapes said:

new cap, rotor for sure, maybe new wires. and when were the plugs last changed?

 

and like you said, new fuel filter!

So it has only been 2 yrs for cap, rotor, wires, plugs. I was just looking back through some pics to get the hours.

I guess I have had a good 2 yrs. Just under 450 hours in 2 years

Time for a full tune up

Thanks

[Sparky450]

58 minutes ago, robbennett said:

How does the boat run? Is it rough at an idle? Anything else seem out of whack with it? 

 

Nothing strange except at WOT. Might be slow out also, I have not weighted it heavy since this began.

Please see above. Will be doing a full tune up.

Edited March 4, 2017 by Sparky450

[Sparky450]

Does the 07 have the in tank fuel pump?

[John I.]

Might want to check out the threads re professionally cleaned fuel injectors.

[Sparky450]

19 hours ago, John I. said:

Might want to check out the threads re professionally cleaned fuel injectors.

That sounds familiar.

That is why I posted here

Thanks

[Sparky450]

Ok

So engine gurus say plugs tell the story!!

What story do these tell?

Thanks

Edited March 5, 2017 by Sparky450

[formulaben]

On 3/4/2017 at 0:25 PM, Sparky450 said:

Nothing strange except at WOT. Might be slow out also, I have not weighted it heavy since this began.

Please see above. Will be doing a full tune up.

Could you be more specific? 

[Steve B.]

Engine temp identical to the higher rpm days? Is water super cold right now?

Steve B.

[Sparky450]

No issue with engine temps. 

What is the deal with 7-8. They are different than the others. 

I did plugs, cap, rotor. And fuel filter last night.  Out for a test run today. And I have the same symptoms. 

[Steve B.]

These engines sit at quite an angle. 7 and 8 tend have some oil leakdown after shutoff, being the lowest level cylinders.

They dont necessarily look bad, but different for sure. You can replace them, or move them around, but I'm guessing your lower rpms will linger.

Steve B.

[MadMan]

On ‎3‎/‎5‎/‎2017 at 1:36 PM, Sparky450 said:

Ok

So engine gurus say plugs tell the story!!

What story do these tell?

Thanks

"Reading" spark plugs is normally looking at the electrodes and insulator in the combustion chamber, not the threads.  Hard to tell from the photo, but maybe they weren't torqued properly and combustion gases were allowed to pass by the threads and past the sealing surface.

[minnmarker]

Have you checked your butterfly valve to make sure it is opening all the way - especially if you have Perfect Pass or similar?

[Sparky450]

Appreciate all the feed back. The blow back explains 7-8. The spark plugs cap and rotor all looked really good to me. electrodes all looked real close to the new ones. I am going to pull the injectors tonight or tomorrow and get them checked. 

Thanks again.