Hi All - Iím new poster on the forum though Iíve been reading posts for a while.
I have a RIB with a 90ís vintage Mariner 40hp 2 stroke with a starter problem and could use some help in diagnosing the fault. Last season the starter motor worked intermittently and this season, having tried to get the boat into service, it doesnít seem to work at all. Although the engine started first time on the chord which was pleasing!
Iím getting no response at all from the starter motor or the solenoid, not even a click. Iíve tested the starter by connecting direct to the battery and and it seems to work fine.
Itís a straightforward system with Mariner ignition switch on the console and battery isolator, both look in OK condition as does the wiring. Iíve bought and tested a new 12v battery and tested the circuits using a Voltmeter according to the steps detailed in the Acro Marine solenoid testing instructions (copied below) with the following results:
Test 1 - 10v
2 - 1v
Test 3 - 0v
(All the results were variable with the Voltmeter fluctuating +/- 1v on most readings)
STEP 1: Check the voltage on the battery side of the solenoid as shown on the left. The reading should be the same as the battery reading (12.6V = Full Charged Battery).
STEP 2: With the voltmeter still connected, turn the key to the start position and read the voltage. The voltage should not drop below 10.0 volts on this terminal. If the voltage drops below 10.0 volts, The battery cable should be cleaned or replaced. If the reading is 10.0 volts or more move on to step 3.
STEP 3: Keep the negative voltmeter lead on the metal base of the solenoid and move the positive voltmeter lead to the terminal marked ďSĒ on the solenoid. Turn the key to the start position and read the voltage. The Voltage could read a little lower than the previous reading but should never be below 10.0 volts. If the voltage is lower than 10.0 volts, You must troubleshoot the start circuit (ignition switch, voltage supply to the ignition switch, neutral safety switch).
STEP 4: Move the positive voltmeter lead to the battery terminal on the solenoid and the negative voltmeter lead to the terminal that the starter cable is attached. Turn the key to the start position and read the voltage. The voltage should read no more than .3 volts. If the reading is more than .3 volts the contacts have excessive resistance and the solenoid should be replaced.
So my problem is where do I start in terms of rectifying the fault? Should I start with the wiring or the solenoid? Obviously I want to start with the most likely parts for repair / replacement but this has stretched the limits of technical competence.
Can anyone help?