I recently installed 2 SBT Yamaha Premium Engines 1200 Non-PV in my 2000 model Yamaha LS2000 and now have 19 hours on the engines. I followed the break-in instruction as described and the engines run great except I can only get a maximum of 5000 RPM and that is just past ½ throttle. Anything past ½ throttle stays at 5000 RPM all the way to WOT on both engines with a maximum speed of 42 MPH with one person in the boat. The entire jet drives were completely rebuilt 6 months prior to installing the new engines and with the old low compression engines I was able to get around 6500 RPM with a max speed of around 47 MPH. I have checked the throttle cables, rebuilt the carburetors, set the high & low speed screen to factory settings & changed the plugs and still no change.
I’m looking for suggestions as to what to do next.
A little more information:
-Oil lines upgraded when the new engines were installed
-No alteration to impellers other than replaced them with new ones
-Replaced tachometers & Speedo meter
-Flushed oil tank
-Replaced oil & fuel filters
-Use only high octane no ethanol gas
-Engines start quickly and idle well
-Replaced all exhaust pipes and seals throughout cooling system
I’m looking for suggestions as to what to do next.
A little more information:
-Oil lines upgraded when the new engines were installed
-No alteration to impellers other than replaced them with new ones
-Replaced tachometers & Speedo meter
-Flushed oil tank
-Replaced oil & fuel filters
-Use only high octane no ethanol gas
-Engines start quickly and idle well
-Replaced all exhaust pipes and seals throughout cooling system
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