yamaha f115 low rpm's

[tzosel]

My 2004 f115 on a 1700 Lund Fisherman will only reach 4500rpm's at full throttle/trimmed. Dealer did a compression test and checked out. He is doing a leak/blowdown? test next. He talked to yamaha and they think the moter was broken in poorly. The moter has 128 hours with 121 at idle (I use it primarly for fishing/trolling). The dealer will contact me after the blowdown test. If yamaha is correct the dealer is saying a 3K bill. I have ran this moter for 3 years with no problems (5800 rpms). If it was broken in poorly why just starting to have the problem?

 

[rodbolt]

Re: yamaha f115 low rpm's

dunno, your usage pattern is abusive but I think your dog is barking up the wrong tree.
why call yamaha until its diagnosed?
I never do compression tests on four strokes as its faster and 10 fold more accurate to start with a leak down test.
what is the fuel rail pressure at the problem RPM?
test wheel YB1624 can be installed, the boat backed down the ramp into the water and the engine should spin to 5600-5800 RPM.
if it cant its broke but you now can test it under load.
if said dealer doesnt have the test wheel find a dealer that doesnt mind spending money on test equipment and personnell training.

 

[tzosel]

Re: yamaha f115 low rpm's

Leak down came back at 4%. He said that was good. His next step was replacing VST and maybe rebuilding/cleaning injectors. Does this make sense? I'll ask him about the fuel rail pressure and test wheel.

 

[rodbolt]

Re: yamaha f115 low rpm's

no it does not make sense, what would make sense is a logical sequence of testing the fuel and ign system using a combination of the fuel rail pressure guage and the laptop.
if everything tests ok the possibly its a clogged/stuck injector.
usual culprit is the filter in the vst, takes an 1 1/2 to 2 hours to clean/replace it.
takes 15 min with the test wheel to diagnose it.