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**Psalm 99** · 08-05-2016, 03:22 PM

Engine Spec:

Engine is a 2004 Yamaha 150 TXRC (2-stroke)

**Psalm 99** · 08-05-2016, 04:00 PM

Sorry: I did not leave the ignition switch on, simply left the key in the switch to check the fuel level.

**cpostis** · 08-05-2016, 04:07 PM

Originally posted by Psalm 99 View Post

Good Morning: After towing my boat to the launch ramp this morning, I found the starter motor running. Wisps for exhaust was coming out the exhaust but the engine, which apparently started while being towed, had shut down. I had left the ignition switch on while I fueled up, then trailed the boat for about 45 minutes to the launch ramp (engine started and ran sometime during this period). Turned the battery pack off to stop the starter motor (it was pretty hot to the touch). Not sure how long the engine ran but I'm concerned about how hot the engine got. Turning the battery pack back on immediately energized the starter motor and turned the engine over (engine apparently did not freeze up). First thoughts are that (1) The ignition switch is bad, (2) The starter solenoid somehow shorted. Its possible some damage was done to the starter motor as it would have remained engaged as the engine idled. Also my water pump ran without water for possibly up to 45 minutes (I can fix this). Sure appreciate any advice you guys can offer.

# 1 (Red Text), could be
# 2 (Green Text) could be
# 3 (Blue Text), probably good

Look at the attached wiring diagram. This is probably the simplest circuit in your motor. Either you are getting voltage to the starter relay coil (the brown wire (Br), or your relay is stuck/welded closed.

Disconnect the brown connector and see if your starter motor still engages. If it does, it's your starter relay.

If it does not, either your ignition switch is bad, or you have a short somewhere between the brown wire and positive, before the starter relay coil.

**pstephens46** · 08-05-2016, 06:54 PM

I would be very concerned with a motor that ran 10 mins without cooling water, not to mention 45 mins. It could be toast.

**pstephens46** · 08-05-2016, 06:57 PM

You know the entire WP assembly is destroyed. So fix that and then work on electrical. Then I wonder if it will run? Could be tragic....

**Psalm 99** · 08-05-2016, 07:10 PM

Sure appreciate the input. Initially (at ramp), I simply turned off the battery bank. This stopped the starter motor but turning the battery switch back on cranked the engine. At home, I couldn't duplicate this (everything worked fine, engine started only when ignition switch went to start). Checked solenoid as follows: coil good (ohm meter), contacts open (ohm meter) until ignition switch turned to 'start' which correctly closed contacts. However, brown wire at solenoid shows about 0.22 volts to ground with the ignition switch simply turned on (not start). When ignition key is removed or turned to 'off', voltage goes to 0.00. Removed switch, and, as it is sealed, simply doused the keyway with CRC electronic cleaner. Although everything works now, I'm thinking of getting a new ignition switch. Thankfully, starter motor seems ok and engine (and water pump) runs smoothly. Any comments will be appreciated.

**TownsendsFJR1300** · 08-05-2016, 07:14 PM

The engine NOT seizing up is a good sign.

It would have gotten everything (fuel/ oil) BUT no coolant.

As noted above, replace all the WP parts(housing included) and then a leak down test or compression test. If it scored the cylinders / pistons, rings, that'd show up in the test...

You can actually do the leak down test before the WP. If there's major leakage your likely putting a new water pump on an anchor..

**Psalm 99** · 08-05-2016, 07:43 PM

Thanks Scott, I'll run the compression test when my wife gets home. Its possible the engine just ran for a few minutes. Not sure why the starter was spinning but not engaging when all this happened. Only way I determined that the engine had run was the last bit of exhaust out the prop.

**Psalm 99** · 08-05-2016, 08:21 PM

Compression test shows 117 psig (+/- about 2 psi) for all six cylinders. Engine has less than 500 hrs on it and it would be a shame to have ruined it. Quite a relief. After spraying electronic cleaner into the keyway of the ignition switch, and placing a volt meter between the brown coil wire at the starter solenoid (ignition key on), the voltage reading dropped from about 0.22 volts to around 0.02 volts after spraying. With key removed, voltage dropped to 0.00. It appears the switch is better but I'm still going to replace it.

**pstephens46** · 08-05-2016, 08:27 PM

Check water pump for heat issues regardless. They can melt rapidly. Be religious about turning off batteries moving forward. I don't turn mine off until I store it but in your situation I wouldn't risk it.

**TownsendsFJR1300** · 08-05-2016, 08:44 PM

Duh....

Gentlemans bet!

Your starter was found to be extremely hot (from cranking). May be toast..

Ignition was off. My money is on your starter relay stuck ON activating the starter(maybe the ignition switch).

The engine NEVER RAN, BUT simply cranked (for quite awhile).

Your water pump is not like the engine was run dry, but IS likely damaged none the less-simply cranking dry.

The engine had fuel/oil while cranking BUT never ran, so "no coolant" is really a non-issue and internal
damage nill.

The compression #'s (and I did not read your compression #'s earlier) are basically verifying the above "Guesstimation" .

Also, "the last bit of exhaust out the prop" could have well well been un-burned fuel dumping out the exhaust. Was it hot or steaming??, The rest of the engine, especially the block, should have been steaming/smelling big time if run that long dry..

**pstephens46** · 08-05-2016, 09:20 PM

Duh my ass. You've seen some of these ops lately! Still waiting on shorted injectors to show up.... Anyhow
Bet the plugs look like crap. Especially if it didn't actually run. Wouldn't the relay look burned?

**TownsendsFJR1300** · 08-05-2016, 09:32 PM

Originally posted by pstephens46 View Post

Duh my ass. You've seen some of these ops lately! Still waiting on shorted injectors to show up.... Anyhow
Bet the plugs look like crap. Especially if it didn't actually run. Wouldn't the relay look burned?

Backyardian guesstimates my good friend!!! And, following the clues/data!

You wouldn't know about the relay stuck closed till you opened it up and looked.

Now, checking to see if there's voltage to the starter WHEN NOT cranking, thru that relay would tell ya!

I did have my starter relay quit a couple years ago. I got about 5 clicks, no start. Pulled the cowl off to start looking, of course it started!! Took it out for the day but I didn't trust out. Confirmed with rodbolt my suspicions and he confirmed. Replaced the switch and cut the old one apart. Sure as $hit, one contact was quite arced up! :

I also learned how to by pass that relay as need be too. I have the short, heavy gauge wire in my on-board tool box to prove it! (along with the SHOP manual too)

The actually working/contact end of the starter relay:

**Psalm 99** · 08-05-2016, 09:41 PM

Good thought that the engine never actually ran. Very slight wisp of exhaust out the prop could well have been vaporized fuel/oil. There was no smell. I will replace the water pump/housing. Compression for this engine is around 115-120 psi and when last tested was just about where it is now. The fact that the starter solenoid's coil was showing a slight voltage across it with the ignition switch on but not engaged tends me toward a bad switch. Starter motor appears to work well. Might have dodged a bullet. I do shut the batteries off when home but leaving the batteries on and the ignition switch on after I fueled up was probably a mistake.

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