Yanmar occasionally won't start, then does.

[akprb]

Symptoms. Yanmar 4j series starts 90% one turn of the key. 10% turn key, nada.

Wait a sec, turn....turn.....vroom. (May be one extra turn or up to three but does start.

Disconcerting.

Fresh start battery, new starter and solenoid last year (swapped out old one just to be safe and that solenoid checked out good)

Replaces Yanmar ignition switch which seemed to help.

On old boat we had similar issue and I recall installing secondary relays as the voltage drop to the solenoid was thought to be to great and that solved.

Anyone have similar issue??????

Side note, we're in Bimini! Say hello :-)

[Suijin]

If it's intermittent and not the solenoid and you get zip, I'd check the wiring and connections. That's all I got.

[akprb]

Been down that road as well. All clean, tight and properly sized (I think). I'm suspect of the distance to the start switch and accompanying voltage drop.

Sigh, not end of world but would be nice to hear "oh yea, Yanmar's do that and here's the fix!"

:-)

[Suijin]

Maybe the panel itself. How old is it?

I doubt the run length would do it. I don't think that would cause intermittent behavior like that.

[donradcliffe]

Just put in a secondary start button switch between the hot lead on the starter and the starter solenoid.

[sailorchic34]

Yanmar solenoid wire from the start button is generally barely adequate when new. Yanmar learned wiring from Lucas electrics (know as the prince of darkness to LBC folks) Yanmar uses non-tined wire and pretty small wires too.

The fix is run a heavy gauge wire, at least 14 gauge, if not 12 from the battery switch to the ignition ( add a fuse) then to the solenoid or add a relay in the existing circuit that gives high current to the solenoid. The typical 30amp headlamp relay available at any autoparts store does the trick.

[VanIslandGuy]

Check the wire connection on the starter itself, then work backwards and check everything else.

We have the same motor, and have the same issue. Culprit is an easy find/fix. Wire is located on our boat on the port side of the engine. Easiest access for us is from the companionway stairs when lifted, and it is on the right when facing aft. This is on my winter to do list for fixes as well.

[Hobie_ind]

My 4JH3-HTE also had a relay under the starter which was there to alleviate the voltage drop through the ignition circuit. Depending on orientation of your engine it's not easy to see. I was having exactly the same issues and eventually tracked it down to a corroded wire going into the body of the relay. I think it can get seawater splashed on it when changing impellers if you're not careful which doesn't help matters. I simply bypassed it and found it worked fine wired straight to the ignition until I could get a replacement relay when I got to Oz.

Fun, fun, fun with boats and wiring.

[daletournier]

Just add the little slave relay, very easy to install.

Sent from my vivo Y35 using Cruisers Sailing Forum mobile app

[Vasco]

The 4 Jh series has what a mechanic told me was a slave solenoid, I used to give it a whack and this worked but finally replaced it. It's on the right side, low down on the engine.

[dlymn]

on the wiring on my 4 JH T E there are 4 connection points from the ignition switch to the starter solenoit. when the starter did the same as yours. I suspected corrosion in one of the connectors. I shorted across from the starter positive to the solenoid positive and it started every time (many times). Finally I ran a heavy line from the ignition to the solenoid and it never happened again.

[Privilege]

I also have exactly the same problem on my 4JH 3c. I know that it's a voltage drop problem, because all I need to do is start my other engine (nearest to the start battery), rev it a little to give the battery added voltage and the other engine starts straight away. I initially thought my battery was dying.

I'm just trying to picture the wiring for the relay...I thought that the solenoid was effectively a relay? So I assume that it takes up more amps to energize than an ordinary relay? Therefore would this simple set-up work? How big a relay would I need? What sort of amps would it need to be rated at? Thanks for the input.

[Geek_Guy]

I second dlymn 's answer. I had the same issue. Though the pattern finally emerged for me that it would not start after warm up.

There are connectors for the wiring from the key to starter and one of the connectors would warm and expand the outside connector.

I cut out the connector and it has been fine for nearly a year.....

[a64pilot]

Originally Posted by sailorchic34

Yanmar solenoid wire from the start button is generally barely adequate when new. Yanmar learned wiring from Lucas electrics (know as the prince of darkness to LBC folks) Yanmar uses non-tined wire and pretty small wires too.

The fix is run a heavy gauge wire, at least 14 gauge, if not 12 from the battery switch to the ignition ( add a fuse) then to the solenoid or add a relay in the existing circuit that gives high current to the solenoid. The typical 30amp headlamp relay available at any autoparts store does the trick.

This is it, mine being 30 yrs old exhibits the same symptoms, one day I will get around to installing another solenoid so that all that inadequate wire has to do is carry enough current to close the little solenoid, that can then close the big one.

[a64pilot]

Originally Posted by Privilege

I'm just trying to picture the wiring for the relay...I thought that the solenoid was effectively a relay? So I assume that it takes up more amps to energize than an ordinary relay? Therefore would this simple set-up work? How big a relay would I need? What sort of amps would it need to be rated at? Thanks for the input.

Attachment 140248

Like SC said, the common little box solenoid that is in cars for windows etc will do the trick they are cheap and widely available.
The starter solenoid is a relay, but it's a big and high amp for a solenoid so use a little solenoid to trigger it, just as is done for electric windows.

Like this, a packet of five with wiring for $12. I'm sure you can find singles or doubles I didn't look
https://www.amazon.com/Support-Relay...Bsolenoid&th=1