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Well, I did look at the NGK site. I am not seeing any evidence at all that the engine is running too lean. In fact, if anything I am seeing that it is running too cool. Not warm enough for the plugs to self clean.
As for the fuel supply questions, the Racor filter etc..
My thinking on this is that once I can get the laptop out on the boat and run it with the YDS hooked up that will tell me if there is an overall fuel restriction problem.
i.e. if the HP pump pressure is within spec...the fuel is getting from the tank to the top end of the injectors okay. If the HP pressure is NOT within spec above 5000 rpm now, then there is still a fuel delivery issue going on.
the last time we took the boat out, day before yesterday, at 4000-5000 RPM we were hanging on with both hands. It would have been a joke to try to operate a laptop under those conditions. We wouldn't have been able to even accurately use the keypad. It's been lumpy.
I am watching the weather. As soon as we have a smoother day we will be back out with the YDS hooked up. That's the next logical step for me.
Right now, we don't know why it starts missing and losing power above 4900 RPM. But it's improved since I replaced the mid pressure canister filter screen.
I did look at the vent yesterday. It's hard to see anything to do with the fuel tank on this boat, but as near as I can tell there should be no salt water issues with the vent. It's amidships and high on the hull. Looks solid. And I doubt it ever gets wet, or that seawater could get into it. That part of the boat stays dry.
Gringo, assuming you have some of these tanks lying around, I'm sure you could rig up something like the attached picture. You just have to make a new center piece that holds the fuel hose. Could possibly make this with a hole saw out of wood or metal, and just put a small gasket underneath to seal it (or leave slightly loose to self vent). Ideally, you would have 2-3 of these 5 gallon tanks, and when you see the level get low, simply switch the hose. If you really want to get fancy, you could put quick connects on the line coming out of these small tanks, and have another quick connect on the primer bulb line.
A new fuel line with primer bulb connected directly to the engine and bypassing the filters would be idea with some fresh fuel. Then you'd really have an idea whether it was you gas tank causing problems or not...
We already did the seperate five gallon tank thing. For weeks. Didn't make any difference. I think that was mentioned on something like page 16 or 18 of this thread. Fresh gas. Not from the boat tank. right from a five gallon plastic jug into the new Racor. Nothing changed.
We already did the seperate five gallon tank thing. For weeks. Didn't make any difference. I think that was mentioned on something like page 16 or 18 of this thread. Fresh gas. Not from the boat tank. right from a five gallon plastic jug into the new Racor. Nothing changed.
Yes, but it seems like you may have solved the problem but introduced a new problem with the 2 micron filter. Can you try running from a clean tank without using the additional 2 micron filter.
It sounds like your engine is starving for fuel at higher RPM's. A 2 micron filter will restrict fuel flow. The 3 micron filter in your vst tank is a high flo filter. If all else fails try forwarding this thread to yamaha. Maybe they will feel bad and send someone to fix it. You never know.
Anyhow, your idea will be easy to check. I can pull hoses off and bypass the 2 micron Racor easily enough. Thats one thing I can say for Contender. that section of the bilge is easily accessible.
Don't know what I would do if I needed to find and replace a fuel sender though.
Yes, but it seems like you may have solved the problem but introduced a new problem with the 2 micron filter. Can you try running from a clean tank without using the additional 2 micron filter.
It sounds like your engine is starving for fuel at higher RPM's. A 2 micron filter will restrict fuel flow. The 3 micron filter in your vst tank is a high flo filter. If all else fails try forwarding this thread to yamaha. Maybe they will feel bad and send someone to fix it. You never know.
Yes this is true but a TPS out of range would cause the same symptoms.
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Now that you have repplaced everything, I no longer feel that fuel starvation is your problem, in fact you may be flooding the pisons at wot, cooling them and the engine with an excess of fuel, causing the plugs to foul almost immediately.
Whatever, I agree with you that this is no longer fun and has now become a waste of time.
But I would still look at a WC266 express, CC or a GB 2680 with engines that can be run in your location on that gas over shallow reefs. The panga will pound you more.
Just got back from a late afternoon run. It went right to 5200 RPM and held it solid, until the temp alarm went off and it shut itself down. I am going to lower the motor on the mount and try again.
Gringo can answer, but I'm pretty sure that way early in the thread he did (raise the motor) when he was trying to solve the water in the lower cylinders problem and before figured out it was a poppet valve issue. Not 100% sure.
Yes, I raised it from all the way down to all the way up. That's about three inches. Even with it raised, the motor cowling STILL gets wet when I first hit the throttle and the bow rises as it comes up onto plane. And yeah, I tilt it all the way 'Bow down' before doing that. It also gets wet when I come off plane, as the following 'boat swell' ( what IS the word for that?) catches up to us and the water level goes about two inches above the gasket where the cowlings meet.
Right now it's looking like my choices are to
a.) keep the motor as dry as possible and just understand that I can never run it WOT, without it overheating,
b.) lower the motor and deal with the consequences of the outside of it and some of the wiring getting dunked at least several times a trip, hoping that the water level inside the cowling doesn't get high enough to get in the intakes, again, or
c.) I dunno. What's another choice? My guess is I lower it one mounting hole and see what happens.
But I am so overjoyed at it running until it overheated that it's just making me jump around like Snoopy doing his happy dance.
If I can work this out, the For Sale sign is going on.
I would still look at a WC266 express, CC or a GB 2680 with engines that can be run in your location on that gas over shallow reefs. The panga will pound you more.
I don't want a bigger boat. I want a smaller boat. And I agree that a cat is a better choice for us here than another panga.
But I need to be looking at something in the 20 ft. range, if I can find it.
Something that would be happy with twin Yamaha 85's on it would be awesome.
