Have Boat Questions? Ask a Boat Repair Expert.
Hello my name is ***** ***** am I speaking with?
What are we working on?
What is the history on this engine? Have you ever personally seen it make full power?
Have you done any spark or compression testing on your own yet?
You have good compression, and you say spark is good. The next step would be going through the carbs and rebuilding them. Has that been done yet?
Hello, my name is***** you still need assistance with this engine?
Ok, First thing that we need to verify is that voltage on the battery with the engine off and then with it running at idle and then at about 2000 RPM. I am looking to see if it is getting over 14.5V DC and the reading on the fish finder is correct when it shows 17V.
Does the alarm test beep when you turn the key to on?
Are your oil tanks full?
Do you know how old the water pump is?
Do you currently have digital gauges?
Analog gauges really do not work for this engine. You would not have the oil pump fill function.
Test the horn circuit for the engine. It should have power in with the key on, but will only have a ground for a few seconds. If that works, replace the warning horn. We need it working to know if you are getting an alarm at WOT or not.
Have you looked into the carbs yet?
For the wiring or the carbs?
Provided that it is still functioning, yes it should.
If the voltage is really at 17V, the regulator would be bad.
The buzzer should only get a ground when there is a fault on the engine.
Yamaha has changed it over the years, some have it, some do not, Hard to tell which does and which dont..
Ever do the running test for the voltage at the starter solenoid?
Set your mixture screws at 1 1/4 turn out for starters, you may need to adjust them once the engine is in the water and at idle.
Have it running and make small adjustments to it.
The floats need to sit level with the body of the carb.
That is either oil level in one of the tanks or overheat, or voltage. Unplug the head temp sensors and see if it stops..
Either that head is hot, or the sensor is bad.
It is going into protection mode. That is why it is slowing.
If the voltage is spiking it is the regulator that is going out.
The engine needs the stats to operate properly. Otherwise it will not come up to temp.
Is the head hot to the touch? Is the sensor still plugged in?
Provided that they are the same sensor, that would work.
You are going to heave a blockage inside the water passages on that head. You will need to open it up and inspect it.