Yanmar occasionally won't start, then does.

[Michael Cobbe]

One reason for starting problems is a loose Solenoid but since you have a new one it seems unlikely, but do check it. The other reason is small hole in the fuel system lets air in and disel out. Use kitchen roll on the fuel lift pump, all connections and fuel filter(s). Run the engine and check the kitchen roll.

[Wotname]

Originally Posted by Uncle Bob

I would guess (yes a GUESS ) that in the case of a three wire relay the metal case acts as the neutral as it is bolted to the engine.

That would be my GUESS too yet captNordy states his Yanmar relay has three wires which are Ground, Postitive from key Switch, power to solenoid. This doesn't make sense as in his description leaves out the necessary positive from battery wire. I assume captNordy is mistaken - either there are four wires on the relay or the case is grounded and he mistaken the purpose of the wire he calls ground.

Nevertheless if he comes back with more information ( a picture of the existing relay and/or the engine model etc), I sure we can work out the facts!

Originally Posted by captNordy

.........How do I know which to go with for the three wires we have on the Yanmar relay (Ground, Postitive from key Switch, power to solenoid)?

[captNordy]

Originally Posted by Wotname

That would be my GUESS too yet captNordy states his Yanmar relay has three wires which are Ground, Postitive from key Switch, power to solenoid. This doesn't make sense as in his description leaves out the necessary positive from battery wire. I assume captNordy is mistaken - either there are four wires on the relay or the case is grounded and he mistaken the purpose of the wire he calls ground.

Nevertheless if he comes back with more information ( a picture of the existing relay and/or the engine model etc), I sure we can work out the facts!

Sorry the delay, we had our mast put back on yesterday so had to pivot jobs. I spent some time inside all the wire loom going to the relay under the starter solenoid. There are three wires, I have a white wire (I believe positive from key switch) on one post and two red wires going to the other posts. One red leaves the relay and goes to battery + on large lug of Solenoid with main battery cable. Other red goes to small tab at top of solenoid by itself (I'm assuming the trigger to close the solenoid. As you can see from the pic, the white wire's connection is corroded as all get out.

Thanks!

[Wotname]

Originally Posted by captNordy

Sorry the delay, we had our mast put back on yesterday so had to pivot jobs. I spent some time inside all the wire loom going to the relay under the starter solenoid. There are three wires, I have a white wire (I believe positive from key switch) on one post and two red wires going to the other posts. One red leaves the relay and goes to battery + on large lug of Solenoid with main battery cable. Other red goes to small tab at top of solenoid by itself (I'm assuming the trigger to close the solenoid. As you can see from the pic, the white wire's connection is corroded as all get out.

Thanks!

OK, that makes more sense! Your existing relay uses it's case as the ground wire. And yes, you are correct, the corroded white wire will be going to the key start.

So to use the relay you pictured upthread, you will need to add a ground wire to pin 85. The ground can be some suitable bolt on the engine or you can run the wire to a negative bus.

The other pins should be connected as mentioned earlier.

Pin 86 to positive from key switch (the corroded wire wire). You may need to follow this back into the loom to find a section of wire that is not corroded or run a new wire right back to the key switch in the panel (better long term solution).
Pin 30 to battery + on large lug of solenoid with main battery cable.
pin 87 to the small tab at top of solenoid by itself.
Pin 87a unused.

Hope that helps.

[captNordy]

Perfect, fired up first two times with no issue, hopefully this did the trick!

Thanks all for the help on this one!

Originally Posted by Wotname

OK, that makes more sense! Your existing relay uses it's case as the ground wire. And yes, you are correct, the corroded white wire will be going to the key start.

So to use the relay you pictured upthread, you will need to add a ground wire to pin 85. The ground can be some suitable bolt on the engine or you can run the wire to a negative bus.

The other pins should be connected as mentioned earlier.

Pin 86 to positive from key switch (the corroded wire wire). You may need to follow this back into the loom to find a section of wire that is not corroded or run a new wire right back to the key switch in the panel (better long term solution).
Pin 30 to battery + on large lug of solenoid with main battery cable.
pin 87 to the small tab at top of solenoid by itself.
Pin 87a unused.

Hope that helps.

[Motorsailer4me]

I know this is an old thread but it helped me so I thought I would add our experience. We bought our 46' motorsailer last fall, sailed it home and put it away for winter while I had double knee replacements. This spring I got to work sorting out all the systems, as best my new knees would allow. The boat had been in heated storage for 5 years. It has two steering stations and when you hit start it would just click for a few trys then start. The starting batteries were old (2008) I replaced with lead acid 1000 CCA units. I also replaced the four 6V golf cart house batteries that were from 2006.

Last weekend after repairing almost every system on the boat we went out for our first overnight on anchor. We went over to 3 Mile Harbor by Easthampton and anchored. It was a beautiful night, the generator, oven, fridge, microwave, windlass, electric winches, sails all worked perfectly.

The next day in very light 3 mph winds we motorsailed past Sag Harbor. I counted 32 Superyachts zooming around about 20 kts. Right as we were passing the south ferry to Shelter Island and dodging superyachts. The engine died. I hit the starter...click click ....every time...no start. I quickly unfurled the jib, the main and mizzen were already up. I sailed in about 1 knot of apparent wind trying to get out of the path of the ferrys and other boats. My wife called Boatow US. They wanted our Lat and Long. My wife was trying to figure that out as I tried to sail us to someplace we could anchor. The Boatow guy said, "We will send a boat right out to tow you to Greenport CA". That was great except we were in Greenport NY! My wife hit the starter again. This time it started and ran perfectly all the way home. We cancelled the tow.

Researching why this happened I think it was we bumped the shifter and the electronic controls cut the engine. Not a big deal if we could just restart. I never wanted that to happen again so decided to put in a secondary solenoid after reading all this. It is an easy job except where our 4JH HTE is located in our boat the only way to get to the starter and solenoid is you have to work laying on the engine. working upside down with only your left hand, I am 6'5...oh and you have to use a mirror so everything is reversed.

I installed a Cole Hearse solenoid. The four-wire type so I could use a ground wire. After dropping the starter stud nut (8 mm metric ss) in the inaccessible bilge numerous times..(bad words were said), Buy a handful of them. Finally, it was time to turn on the power and look for sparks and smoke. It worked!

It starts now every time even from the outside steering station. It was worth the painful 3 days of boat yoga. This forum is a great resource.