Volvo MD22L engine wont shut down

[Tkeeth]

Hi, hoping someone here has a path for me to travel. Recently, I had an intermittent issue with engine shutdown and would have to go down and manually shut down. I have replaced the stop solenoid and checked voltage at 11.75 volts. It tends to happen when the engine is warm only. Anyone seen this before?

[a64pilot]

OK, you replaced the solenoid, so my guess is wiring, 11.75 doesn't sound right to me, especially if engine is running, less than 12V is a dead battery so I going to assume you have a high resistance connection somewhere and when you try to draw amps from that wire, voltage drops off drastically.
Connect your multimeter to the wire and have someone hit the stop switch and hold it, see what happens to voltage.
Resistance often gets worse with higher temps I believe.
Could be dirty contacts in the switch too,

[Tkeeth]

11.75 is with the key, without it voltage is zero. Ill start tracing the wire out and see if i can find a connection somewheres. I wasnt sure about the 11.75, but was told that the drop was likely due to the length of run. A solution was offered up that if i cant find it to install a relay on it and use direct power.... fixing to heat it up then try jumping direct from battery. If that works it should confirm resistance connection?

[a64pilot]

The relay thing is a very common fix for older systems, what happens is as the wires age, they oxidize and resistance builds and less voltage goes down the wire until eventually one day there just isn't enough, sort of a normal aging process I beloieve for Yanmars for example, and if you had a VW bus from years ago, you just lived with the fact that the generator light would dimly glow at you at night even with the generator operating properly.

Ideally the voltage you read at the solenoid should be very close to battery voltage, if battery voltage is in the high 13's and your only getting 11.75, then you most definitely have a problem, it could be just loose or dirty connection, and check the ground side too, ground gives me more trouble than the positive side it seems

[Tkeeth]

Ok, thanks for your help, tracing wires now

[Svalan]

Hi, just have had the same problem with my Volvo Penta TMD 22. The problem - according to my very professional mechanic - was a temperature sensor in the engine that had to be replaced and a new ignition switch. It seemed to be a well known problem for elderly engines (1999). Hope this helps.

[tkeithlu]

That's an intermittant use solenoid that takes a bunch of amps, so wire size, run, and all those corroded connections are likely sources. It's probably moving part way or briefly, enough to stop a cold engine but not a warmed up one.

[Tkeeth]

I am leaning toward the corrosion issue. I traced the wire as much as i could outside the protected harness. Could not find anything. I unplugged and replugged all the connections as well as any harness connection i could find and now I cannot replicate the problem. If i resurfaces, i belive I will opt for a $4 relay and make direct connection to the battery and be done with it. Thanks for all the help so far, i doubt its fixed, but it isnt happening at the moment. I hate these little bugs

[Zai]

How about to get rid of the solenoid, wire and switch and install a simple push/pull cable at the helm?

[tkeithlu]

That's what I use - actually a wire inside a flexible spring sheath made up from old bicycle derailleur cable covers. One knob at the helm pulls the manual stop, and the other releases the spring-loaded air flap to shut off air to the engine if the first fails or I get a run-away. So far, I have not needed the emergency stop. Very simple, very reliable.

[Tkeeth]

Its been considered..as a matter of fact it was my first plan....logistically it seems pretty difficult to set up.

[tkeithlu]

If it turns out to be a solenoid problem, be aware that the heavy truck/equipment parts people have bunches of stop solenoids cheap. Westerbeke wanted $1,400 for a run/stop solenoid for my M25 Universal genset; the truck people had the exact solenoid for less than $200. The starter is a Kubota at $68, not a Westerbeke at $1200. These engine manufacturers don't design new peripheral parts; they take a suitable unit off the shelf, and if you can ID what they used on the internet, you can save a bunch of money.

[Tkeeth]

Thanks, i already replaced the solenoid, ordered one from uk for $70 instead of volvo $485, same deal going with the ignition switch, they want $300 for it. I am sure I can find a cheaper replacement, or the $4 relay