Trojan Boat Forum

First off, many thanks to P-Dogg for helping me find the manuals for my boat - super helpful!

Okay, so now I've reached my limit on starter/solenoid troubleshooting my port engine. I've just cashed in on the warranty for two brand spanking new batteries, and I can't get the starter motor on the port side to engage.

Unfortunately, the wiring diagrams, while very clear on every other section, have so many lines going to the starter solenoid that I can't make heads or tails of it all.

Is there anyone here that has made any sense out of which wires go where? The colors that they are (supposedly) labeled with don't help either because at some point, somebody seems to have just painted everything blue....

I also need to start the grand voyage of locating the neutral safety switch and ignition fuse, so if anyone happens to know where those were placed on Trojan Tri-cabins, I would be very appreciative.

Thanks!
-Jbrem

Here is my very scientific attempt at very scientifically figuring this out...

You do have your photo labeled correctly . . The ignition feed will not effect starter operation so ignore it while diagnosing the starter . You should have battery voltage (12V) at all times on the big terminal . With the switch in the start position you should have 12 v at the S terminal

Safety switch is on the transmission


The main power wire looks dirty , I would clean the connection

Awesome, thanks! I'll put the multimeter on the terminals when I get home tonight. Picked up some wire brushes yesterday as well because of how dirty the electrical connections all are.

-J

OK, so here's what I measured with the help of my assistant (girlfriend was a good sport.)
To me, this seems to say that there is a problem with the starter relay or the neutral safety switch? I ensured that the gear was shifted into neutral at the console. The 6v (on start) coming from the ignition coil does have me a little stumped though, is that a step down voltage after 12v passes through the alternator perhaps?

Again, thank you for humoring my ignorance - hoping to get this solved before our next cold snap hits this weekend so I can leave the boat alone without worrying about a freeze.

Thanks!
-J

jbrem003 wrote:OK, so here's what I measured with the help of my assistant (girlfriend was a good sport.)


To me, this seems to say that there is a problem with the starter relay or the neutral safety switch? I ensured that the gear was shifted into neutral at the console. The 6v (on start) coming from the ignition coil does have me a little stumped though, is that a step down voltage after 12v passes through the alternator perhaps?

Again, thank you for humoring my ignorance - hoping to get this solved before our next cold snap hits this weekend so I can leave the boat alone without worrying about a freeze.

Thanks!
-J

The 6 Volt from the coil is normal as its going thru a resistor , nothing to do with your issue that's why I said ignore it . You should be getting 12 volts to the S terminal on start , that is your issue . Possible n/safety switch or starter relay . check voltages there . You photos by the way are a big help

jbrem003 wrote: To me, this seems to say that there is a problem with the starter relay or the neutral safety switch? I ensured that the gear was shifted into neutral at the console. The 6v (on start) coming from the ignition coil does have me a little stumped though, is that a step down voltage after 12v passes through the alternator perhaps?
-J

Even if the gear shift is in "neutral" it may not be. I often have to "jiggle" my gear shift lever while holding my key in the start position to get my engine to start. Have someone hold the key in the start position and "jiggle" the gear shift lever forward and back while you check the voltage at the "S" lug.

Okay, new update.

I got 11.5v at the S terminal after juggling the neutral position of my transmission. (Good tip!) but I'm still only getting one click from the starter when I put the relay into the start position.

I'm guessing this means the starter solenoid or the starter motor are bad.

Update:

I shorted across the two terminals of the solenoid (got a tiny spark) and the starter motor declined to turn. It looks like the starter motor has seized...is there any way to get the engine running without this motor or any tricks anyone knows to verify for sure that this is the problem?

Guess I'm pulling the assembly apart either way.

Have you ever run this engine, or is this a new problem? If it has never been run, you might try to turn it over with a socket on the crank bolt. After sitting for years, the engine could be stuck or even hydro locked.

If the engine turns over, it is probably worth the effort to remove the cable to the battery, clean all corrosion from the cable, terminal and bolt, then reinstall. You can have plenty of voltage, but no ability to supply current when the path has high resistance due to corrosion.

If you are ready to swap out the starter anyway, you can remove it from the engine and try it out by itself. You can verify that it engages and the gearbox is not trashed.

If you have straight weight oil in the engine and it is very cold, that can be quite difficult for a weak starter.

I bought the boat about 4 months ago and the engine was running hot and slightly bogged when we took it on sea trial. The seller had the carbs rebuilt and we checked flow of all the parts of the engine fuel, oil and coolant side to make sure nothing was clogged and got the engine running ok enough for us to close on the sale.

The engine ran for a few weeks. It then quit out on day 1 of a 3 day voyage and I just now am starting to have the time to diagnose what was wrong .

Is there somewhere I could watch a tutorial on how to deal with the crank suggestion you made and learn more about what hydro locking is?

My current guess is that the battery being bad and numerous restarts caused the starter to go bad, but I'm happy to try more testing if this hydro lock is indeed the issue. I have plenty of new oil and coolant to change out once it gets run up to temp but am expecting to find something else wrong at this point based on how it's been behaving and trying to take it one step at a time.

-J

It is good to know that it has been running recently!

Here is a video of hand cranking an engine. Basically, you use a socket and breaker bar or ratchet to turn the bolt on the crank pulley, turning the crankshaft and making sure all the moving parts actually move. There should be some resistance to turning over due to the pistons compressing the air in the cylinders, but you should be able to turn it over slowly.

https://www.youtube.com/watch?v=APuauc1y2lA

Hydro locking occurs when water or some other fluid gets into the cylinders. Air can compress, but water cannot, so the engine will not turn over. If this happens, you can bend a rod if there is enough force turning the crankshaft. For boats, this typically happens when the exhaust manifolds get old and leak water into the engine through the exhaust valves. Overheating is another sign that the manifolds may be failing, though there are other reasons for overheating as well.

If the engine is hydro locked, removing the spark plugs will allow it to turn over as long as there is not too much rust in the cylinders.

Getting back to your problem, I would want to know if the problem is the starter not engaging or if the engine is not able to turn over. That is why I suggested putting a socket on the crank and making sure the engine is not locked up.

There is a secondary starter relay under the blue box. It is installed by mercruiser as sometimes it is a long distance for start relay to work of helm. That said I had to buy a completely new starter as my old one hung on and would not release. It was over spun by the engine upon start up and slung solder out of the armature. I replaced the secondary starter relay at the same time and work fine now. The new starter is a modern geared drive and turns engine better than old one which I could not get parts for. It was only 160 dollars or so, worth it to me. You may have a stuck main starter relay. In old days you could take the delco remy relay out take it apart and turn the contact around for a new contact surface and voila, I could not as armature fried.

Either starter relay could be causing the problem.

WayWeGo wrote: Getting back to your problem, I would want to know if the problem is the starter not engaging or if the engine is not able to turn over. That is why I suggested putting a socket on the crank and making sure the engine is not locked up.

So.... I tried turning over the engine with a socket and since it's the port side engine and turns CCW, the bolt came loose instead of turning the engine... I think that since it's reversed this technique is not really effective. I was able to get the starboard side engine to rotate just for comparison to see how much torque was needed though. I've tried using some of the other bolts to create a lever as well but they all just want to unscrew before I can generate enough torque to turn the crank pulley.

Try turning it at the alternator ( belts must be tight ) 15/16 socket should do it .

You do not need to turn it in the correct direction, you are just trying to determine if the engine is seized up or not. If it will turn in either direction check for a bad starter.