volvo penta 7.4 won't turnover

[Scienceguy]

Hi All,

Here's the worst; an intermittent problem. The stbd engine on my 406 Aft cabin will simply choose not to turnover (of course it turns over and starts nicely when sitting in the sunshine on a beautiful day and you don't have to go out anyway. It's always when you're about to go over the falls............)! It will start with the key on and shorting out the contacts on the solenoid at the starter (that's how I got home).

Wiggling the shift lever to jostle the neutral safety switch doesn't seem to have an effect.

The key switch works according to my multi meter. I thought I had it when I shorted out the wires and it kicked over indicating perhaps poor connections so I then cleaned the terminals and really tightened them down. Turned the key and BOOM. Tried it again a few times and boom problem solved! That is Until I tried starting it the next day!!!! So the key switch seems to be out of the loop.

There are two relays together on each engine. I took the "good relays" out of the Port engine and was going to try them in the stbd engine but needed to make sure it was in its non-functioning mode. While on the bridge I decided to try the port engine without the relays to see what would happen and lo and behold it turned over but wouldn't start. That seems to indicate that they are not needed to get it to turnover.

So what's left? Any ideas?

Thanks a lot

[mjk1040]

Something I have seen a lot lately is the wiring harness at the engine being bad, corroded and bad connections. The next time it happens, see if you can get someone to wiggle the harness while the key is in the run position. People sometime step on them or pull on these harnesses and ruin them. Had 2 Volvo engines in carvers do this just this season, a 1989 Santego and a 2001 356 AC/MY, both with Volvo's! Mike

[Scienceguy]

Mike,

Thanks. I sure will give that a try the next time it acts up.

[Viper]

I agree with Mike on the harness. Also consider that the neutral safety switch might be faulty. I can't recall if your application incorporates a slave solenoid or not (I think not) but that would be another pretty common possibility. Have someone at the helm turn the key while you listen in the engine bay. Does anything click when the key is turned to the start position?