Spark plugs and performance issue.

[USWaker]

So I was out last weekend and experienced a noticeable decline in performance compared to previous trips. The last couple trips it just doesn’t pull us out of the water as efficiently as we’re used to. So I went down the typical path of checking that simple stuff. Found an owners manual. Decided to check the plugs. The outer bank had some motorcraft CYFS12F plugs. The gap was 0.050”. The book said it should be 0.044”. Started removing the inner plugs… they were different. CYFS12NPG?? Similar gap..

any thoughts on the plugs from someone who has removed an original plug set?

was going to run some injector cleaner…

just takes longer than usual to get up to surf speed. And idles a bit rough.

it’s a 2017 r21 with 360
ive owned it for about a year so I don’t have any service history prior.

[flyboy]

Burn looks good? I replaced my plugs, rotor and cap this year. I also was experiencing bogging down on acceleration, but now she runs like a bat out of hell.

Replace the plugs.

[freeheel4life]

The upper plug and lower plug are two different plugs from the factory. Also just fyi, left coil packs and right coil packs are different on the Raptor.

With the boat running in neutral at about 1500 RPM pull the clip from engine harness off of each coil one at a time and listen for an RPM change when it's unplugged then original tone when you plug it back in. If you unplug one and get NO change that's the dead hole. Either coil pack or injector.

IIRC the 360 doesn't run a fuel pressure sensor and you have to buy a special adapter from indmar on that model if you want to test FP(later years got a Schrader valve to test).

Do you trailer or store the boat on the water?? If you trailer have you been noticing more whater than usual when you pull the bilge plug?? If in the water lift the floor and look and see if you have a bunch of water at the low point of the boat. Typically longer planing times is a result of the boat being heavier.

[USWaker]

Thanks for the pointers. I have new plugs. I noticed that one plug is made for forward direction spark and the other is for revers direction spark, which makes sense since they share a coil. I found the same plug that is dual platinum so it will work both ways. Once I get them in I’ll hook up water and check for a dead hole. It’s defiantly not taking extra water in the Bilge. I can hear a intermittent miss at low rpm which is what lead me to checking plugs, injectors etc… we’ll see.

[USWaker]

Ok, new plugs in. Found an exhaust leak where the port side Fallopian tube connects the the exhaust manifold. Fixed that. Seems to run good. We’ll see Monday when I put it under a load.

[USWaker]

So I think I PinPointed the issue. I can’t believe I missed it… I found four holes in the bottom of the boat. So I filled those with liquid nails. I also noticed water dribbling from where the shaft comes out when I was plugging the holes, so I coated the shaft with Pam non-stick and put silicone all around the shaft where it comes out. I used the blue so it matches the boat.

[freeheel4life]

Sooooo....Water is supposed to coming out of the shaft seal(where the shaft comes put of the boat). It has a carbon seal that is lubed with water from the engine. If you had just run the boat on a fake a lake it was likely residual water draining out thru the dripless packing.

[USWaker]

Lol I was just funnin with you guys.

[USWaker]

Got it in the lake. Runs very noticeably better.