Yamaha lf200 four strokes not planing out

[Kato8181]

I have 2- 2006 Yamaha 200 4 strokes that start and idle but underload they will not get above 1200 rpm’s. I have replaced all the fuel lines, fuel filters, fuel separators, spark plugs and high pressure fuel pumps. Also had the gas tank cleaned. Motors have good compression. Also had the binnicles replaced. There is a little bit of back fire. I’m at a lost. I have spent over 6000 at the mechanic and no answers. When I brought the boat home I noticed there were multiple leaks and fixed those. Seemed a little better but still won’t go above 1200 rpm’s even when shifter is all the way down. Any input would be greatly appreciated.

 

[saltchuckmatt]

I have 2- 2006 Yamaha 200 4 strokes that start and idle but underload they will not get above 1200 rpm’s. I have replaced all the fuel lines, fuel filters, fuel separators, spark plugs and high pressure fuel pumps. Also had the gas tank cleaned. Motors have good compression. Also had the binnicles replaced. There is a little bit of back fire. I’m at a lost. I have spent over 6000 at the mechanic and no answers. When I brought the boat home I noticed there were multiple leaks and fixed those. Seemed a little better but still won’t go above 1200 rpm’s even when shifter is all the way down. Any input would be greatly appreciated.

Did you buy them that way or did it just start happening? The most common thing of it happens to two motors at once would be fuel but you seem to have address that. What did your mechanics say?

 

[jimmbo]

The joys of Computerized 4 Strokes, well Computerized 2 Strokes as well, very difficult to Diagnose and/of Fix

 

[99yam40]

did they hook the motors to a laptop with the proper software to look at everything?

 

[dingbat]

I have 2- 2006 Yamaha 200 4 strokes that start and idle but underload they will not get above 1200 rpm’s. I have replaced all the fuel lines, fuel filters, fuel separators, spark plugs and high pressure fuel pumps. Also had the gas tank cleaned. Motors have good compression. Also had the binnicles replaced. There is a little bit of back fire. I’m at a lost. I have spent over 6000 at the mechanic and no answers. When I brought the boat home I noticed there were multiple leaks and fixed those. Seemed a little better but still won’t go above 1200 rpm’s even when shifter is all the way down. Any input would be greatly appreciated.

Cleaned VST tanks and filters?

Assume motors has had diagonitc software run.
Any codes? Hard to believe it’s limits to 1200 rpm w/o codes

Tried running engine off an alternative fuel source?
Connect a small tank of fuel as close to fuel pump as possible. On my motor it was easier for me to pull the fuel line off the input of the fuel pump. Made up a fuel line with clear plastic tubing and a primer bulb. Connect line to fuel pump, drop other end in a one gallon gas can. Quickly rules out upstream fuel delivery components from contention

 

[Kato8181]

We bought the boat but took it to the mechanic to have it looked over before we started it. So that was all the work that he did to it. But we did not clean the gas tanks until after we tried to start it and had those issues. So he clean the gas tank after that but the whole system hasn’t been cleaned again. There was quite a bit of sludge in the gas tanks. The mechanic told us there are no codes.

 

[saltchuckmatt]

We bought the boat but took it to the mechanic to have it looked over before we started it. So that was all the work that he did to it. But we did not clean the gas tanks until after we tried to start it and had those issues. So he clean the gas tank after that but the whole system hasn’t been cleaned again. There was quite a bit of sludge in the gas tanks. The mechanic told us there are no codes.

Seems pretty simple then. You or the mechanics need to go through the fuel system again. (Bad fuel) Unfortunate, buy it's what the evidence points to. I'm assuming after cleaning the tanks the main prime fuel filters were changed.

 

[jimmbo]

Sometimes once the Injectors get crud in them, the only choice is replacement

 

[Kato8181]

update:
I went through the whole fuel system and cleaned everything to the injectors. Here is a picture of what the first mechanic did and and pic of what the second one found.


I’m at a lost.. after I cleaned everything and ran ALOT of sea foam it was idling a lot better. Took it to the lake and as soon as I tried to get above 12rpm, I could push throttle all the way down with no difference. And there was still a little bit of back fire.

Could the binnicles have been hooked up wrong? The first mechanic was a very good Amish man but I don’t think he had the diagnostic equipment to really figure it out. I’m at a lost

 

[Kato8181]

Bump

 

[99yam40]

no one has a clue if your rail pressure is in spec and stays in spec when the motors will not increase RPM.

I have no idea what that 1st pic is supposed to be of in post #9

 

[Kato8181]

How do I fix that

 

[99yam40]

How do I fix that

how do you fix what?

 

[Kato8181]

I mean how do I test that. And if it’s not at the right spec does that mean it just needs adjustment or is something in the fuel system clogged

 

[saltchuckmatt]

I mean how do I test that. And if it’s not at the right spec does that mean it just needs adjustment or is something in the fuel system clogged

You got a detailed description of what's wrong from an outboard shop. Just fix those things and your go to go.

 

[99yam40]

I mean how do I test that. And if it’s not at the right spec does that mean it just needs adjustment or is something in the fuel system clogged

hook up a pressure gauge to the rail and see what it reads and if it holds when raising RPM.
worry about what to do after you prove that is a problem, if it is a problem

I finally tried reading you sideways pic, and it says your rail pressure is not in spec.
I would guess your high-pressure pumps are not running, depending on where the last tech took readings (maybe he was not reading rail pressures