I recently purchased a Sunbird 1995 20' with a 135HP motor. After 2 mechanics changing all electrical I get a buzzer at 4000 rpms. Begines cutting out. I can shut things off and set and start it back. It runs great at 3800 rpms. Seems a little low to me. Has anyone have any suggestions maybe a fuel issue? Not sure but any help would be great.
Yes sir everything. Some things twice, between the 2 of them the motor was rebiult all except the internal parts which are all good. Original problem was not starting and the owner took it to a mechanic that was replaing parts one at a time. I then took it to another one that I knew and he went through everything the other mechanic did and some. It was backfiring and not starting.
Thanks for your reply but all that has been taken care of and yes that was the original problem. Now since it runs well and starts up once it reaches 4000 rpms and runs for a few mins it backs down and will only run at 2200 rpms without cutting out. You can shut it down wait 2 mins it will again take off at full power. If I keep it at 3800 rpms it will run allday long
If the motor is the 130 HP looper outboard, it does have S.L.O.W. which in combination with the constant horn tells you that at least one bank of your cylinders has overheated and that the cooling system needs repair.
S.L.O.W. is controlled by the powerpack and the temperature switch in the cylinder head is the sender.
That model number is for a 1995 130 HP loop charged motor, which is good.
If the propeller has not been changed, then the motor should still do 5,600 RPM if it is set up correctly.
The immediate concern would be that you have indicated both warning horn and S.L.O.W. warnings which should not be ignored.
Usually, that would indicate that a new water pump impeller is due, and that the thermostats should be inspected.
If the propeller has too much pitch, it would lug the engine, overwork it and make it run hotter than it should. It would also prevent you from reaching the right RPM which should max at 5800 RPM to 6000 RPM with a normal load.