2012 3.0L TKS runs great with muffs, but slow on lake...

[cyclops222]

Post # 97 is the correct reason for the problem.

 

[GeorgioP07]

Installing the new anti-siphon valve tonight, re-testing fuel pressure and spark color.
One guy on Reddit had similar loss of power on the water past 3K RPM, after coming out of Winter storage.
His deduction was:......" Spiders built a nest in your vent tube".
I supposed I can shoot some carburator cleaner down there.
Would that explain that the performance restored when the boat made a sharp left turn a few times this Summer, or is that just a long shot? It was stored last Winter in a barn.
Most arthropods are killed by gasoline vapors. That would be strange indeed.
Thanks.

 

[alldodge]

Would that explain that the performance restored when the boat made a sharp left turn a few times this Summer, or is that just a long shot?

IMO no

 

[Scott06]

Installing the new anti-siphon valve tonight, re-testing fuel pressure and spark color.
One guy on Reddit had similar loss of power on the water past 3K RPM, after coming out of Winter storage.
His deduction was:......" Spiders built a nest in your vent tube".
I supposed I can shoot some carburator cleaner down there.
Would that explain that the performance restored when the boat made a sharp left turn a few times this Summer, or is that just a long shot? It was stored last Winter in a barn.
Most arthropods are killed by gasoline vapors. That would be strange indeed.
Thanks.

easiest way to tell is crack your gas cap open if it is under vacuum then your vent is plugged, and if you open it it will remove the restriction getting fuel out of a tank under vacuum

 

[GeorgioP07]

Hello,
I installed the new anti-siphon valve and dip/ pickup tube and ran at idle.
I get 6.5 PSI now just before the carburetor, as opposed to 4.3 PSI at idle with the old anti-siphon valve. The temperature was 72F when that was done. With the new ignition coil, I am only seeing blue in the sparks across all 4 wires. Very unlikely that I can test this updated configuration out on the water before Winter, as it's getting cold and raining a lot. I am getting all of my winterizing supplies ready, which by the way I noticed that my Mercruiser 3.0L service manual says that the spark gap = Plug Gap .035 in. (0.9 mm), but the label on the top of my flame arrestor says it should be .045in. I have been using the .045in since this the original flame arrestor.
Let me know what you think. Thanks.

 

[alldodge]

The manual has a misprint, the LTS plugs should be gaped at .045, use what is on the flame arrestor

 

[ESGWheel]

George,
The increase of pressure is a positive sign, and I am keeping my fingers crossed that all will be good. Its unfortunate will need to wait until next season, and I really am looking forward to that on the water test.

On another note: George you get my personal “Original Poster of the Year” award. You have stuck with this forum despite all the dead ends and frustration. More importantly you have never given up on finding a solution and followed thru on the recommendations and posting the results. You remained curious and willing. Your tenacity and constant communication are a role model for all Original Posters. My hat is off to you sir!

 

[Scott06]

Hello,
I installed the new anti-siphon valve and dip/ pickup tube and ran at idle.
I get 6.5 PSI now just before the carburetor, as opposed to 4.3 PSI at idle with the old anti-siphon valve. The temperature was 72F when that was done. With the new ignition coil, I am only seeing blue in the sparks across all 4 wires. Very unlikely that I can test this updated configuration out on the water before Winter, as it's getting cold and raining a lot. I am getting all of my winterizing supplies ready, which by the way I noticed that my Mercruiser 3.0L service manual says that the spark gap = Plug Gap .035 in. (0.9 mm), but the label on the top of my flame arrestor says it should be .045in. I have been using the .045in since this the original flame arrestor.
Let me know what you think. Thanks.

Obviously more pressure is better only water test under load will.
luckily you have one of the easiest engines to drain , two drain plugs…