Yanmar alarm and hydrolock

[Richard L]

Hi all,

When trying to start the Yanmar 47 port engine on our cat the alarm would sound necessitating turning the battery switch off then on again. Sometimes it would take up to ten times to start the engine or sometimes the engine would start right away. Several mechanics in the Caribbean looked at it and after a new starting battery, alternator, the final verdict was hydrolock and we had to have the port engine rebuilt. Two weeks later it is doing it again. Did we just spend $$$$$ for nothing?

Thanks for your help,

Richard

 

[NYSail]

When you’re starting your engine do you close the thru hull fitting if you’re having problems? If not you will be flooding your engine. However most starting problems with Yanmar engines relate to the wire harness from the starter to the panel. Did the mechanic or you check the voltage?

 

[jssailem]

Welcome @Richard L to our band of happy sailors. First thing some might question, why do your need two hulls and two engines when one is often sufficient?

But that is way off base and of no consequence to this discussion.
No way of knowing if the $$$$ were not spent wisely. What is relevant is the age of the engines. How they are wired between the batteries and the starter. And are there signs of water in the engine when you try to start and start and start the engine.

The turning battery off and then on again serves to reset the electronics of your engine alarm. I would look at that circuit since you said once you turned off the batteries (cut the power to the circuit - rebooting the system) and turned them back on it started with out a problem. Perhaps there is corrosion on connections (should be an easy fix - clean the connections and spray some corrosion protection). Or worse something in the circuit is unhappy (no info on the newness of engine. This may be a new computer managed engine and need technical examination if one of the modules is acting up - yes this is the area where $$$$ and special knowledge comes into play.)

I hope it is simply a wire unattached or a bit os common corrosion. Best of luck.
Pictures and detail is always helpful to do this long-distance problem solving.

 

[dlochner]

First thing some might question, why do your need two hulls and two engines when one is often sufficient?

So he has a spare engine to get home on. Every Cat sailor knows that!

 

[Davidasailor26]

I have a few clarifying questions -

the alarm would sound necessitating turning the battery switch off then on again.

What alarm exactly goes off? Many yanmars have an oil pressure alarm, but that will alet whenever the ignition is on and the engine isn't running. There is often a few second delay between turning on the ignition and the alarm starting, and if you don't start the engine in the mean time the alarm will go off. If that's what you're hearing it's normal.

Sometimes it would take up to ten times to start the engine or sometimes the engine

How long are you cranking each time? If just a couple of seconds that's ok. If you're cranking for, say, 15 seconds each time then you're likely pulling in enough water to back up into the cylinders.

the final verdict was hydrolock and we had to have the port engine rebuilt.

So when they rebuilt it did it have water in the cylinders?

Also, when you try to start it does the engine turn at all, or is it completely stuck? If it's turning then it's not hydrolocked, it's just not getting enough fuel, air, or compression. If it's not turning then it could be hydrolock, or it could just be a bad battery connection. The battery connections could be verified by checking the voltage at the starter itself.

 

[dlochner]

The known problem with the Yanmar wiring harness involves the power supply to solenoid. Power to the solenoid is picked up at the starter positive post, runs to the key switch and back to the solenoid. Due to undersized wiring and possible corrosion, this circuit is suspect. By the time the current gets back to the solenoid there is not enough power to fully engage the solenoid, it clicks but doesn't engage the starter. It is also intermittent.

There are a number of fixes out there, all have the same basic function, provide more power to the solenoid. The cheapest easiest fix is to replace the suspect wire with 10 gauge in a single continuous run from starter to switch and a single run from switch to solenoid.

After a new battery, a new starter, and numerous frustrating starting moments, I replaced the wire from the switch to the solenoid with 10 Gauge and tapped the main positive bus bar for power to the key switch. No problems since the change.

 

[Whatfiero1]

I'm inclined to believe he has a bad riser and as others have said backing water into engine. And big money spent bought a New riser maybe head work. But probably not engine unless saltwater was left in block. But that's a turbo motor so bad injectors or turbo can cause hard starting. Ya need to figure a starting procedure for that motor or get a New mechanic. I open seacock halfway then start motor then run down and open all way. But only on cold starts

 

[MitchM]

at the advice of larry berlin at Mack boring co., yanmar's east coast distributor, on my yan 2GM20F i wired an extra 'momentary' start button within 2 feet of the engine and raw water seacock. it allowed me to avoid the panic run , pushing the key start switch in the cockpit at the b panel then running down the companionway stairs to quickly open the raw water seacock .