The wiring harness for the Lehman SP 135

[JDCAVE]

This is new territory for me so apologies for the newbie questions. My oil pressure gauge was highly erratic the other day. I phoned the local concern, Industrial Engines and it went to voicemail. I phoned and eventually got through to Brian Smith at American Diesel. I suspected it was a faulty oil pressure sending unit but he said 9 times out of 10 this problem is typically the wiring harness, which in the case of the Ford Lehman is not well made, with undersized wiring etc. He suggested “cleaning up the contacts and spraying the pin connector with contact cleaner, etc.

1) Has anyone dealt with this before and what was the approach to the problem?

2) How many instruments and sensors are part of this connectivity? I noticed the “engine stop” took longer than normal to engage?

3) Do the connections run from the engine to the terminal strip connections in the engine room?

Photos would be helpful!

Thanks!

Jim

 

[kchace]

Absolutely check all the contacts first. Especially any "spade" connectors - they commonly have intermittent connections after a long period of time. Just a few weeks ago I had abnormally high oil pressure indicated on my port engine and it was the spade connectors on that engine's sending unit. But don't forget ground and power to the meter, too.



Ken

 

[rgano]

This sounds like a good question for experienced KK owners to help you with, but in any case, it makes sense for you to follow your wiring from engine to gauge and thence to ground just so you know where it all is. And as Ken said, pull and check them all. Sometimes the stuff on a boat just wants to be touched and feel the love.

 

[catalinajack]

I have Lehman 120s. I simply ran new wires for my new oil pressure and temp gauges.

This is new territory for me so apologies for the newbie questions. My oil pressure gauge was highly erratic the other day. I phoned the local concern, Industrial Engines and it went to voicemail. I phoned and eventually got through to Brian Smith at American Diesel. I suspected it was a faulty oil pressure sending unit but he said 9 times out of 10 this problem is typically the wiring harness, which in the case of the Ford Lehman is not well made, with undersized wiring etc. He suggested “cleaning up the contacts and spraying the pin connector with contact cleaner, etc.

1) Has anyone dealt with this before and what was the approach to the problem?

2) How many instruments and sensors are part of this connectivity? I noticed the “engine stop” took longer than normal to engage?

3) Do the connections run from the engine to the terminal strip connections in the engine room?

Photos would be helpful!

Thanks!

Jim

 

[syjos]

I ended up rewiring the original gauges to the senders instead of trying to troubleshoot faults when they occurred.

All the issues were with the wiring. The gauges and senders were fine.

I guess I made my own harness. I was able to declutter the gauge wiring.

 

[Comodave]

I have spoken to Bob Smith before he passed about the wiring and he agreed that the wiring is undersized and problematic. Unfortunately in my case the wiring chase to my helm on the flybridge is jammed almost full. I don’t think that I could possibly fit new wiring for the gauges in it.

 

[JDCAVE]

Thanks guys. All good advice. I will work through this when I get back. I’ll also follow up with Brian at American Diesel.

Jm

 

[Dcbeach]

My KK42-113 has the same issues. I found it to be the untinned wire.
My solution is to attempt to remove the crimp connector, splay out the wires, polish them with a Dremel tool wire wheel until bright, install a new connector. I do both sides.
I attempt to remove the connector using relatively new electrical pliers which have sharp “teeth” apply pressure opposites of the crimp. This generally opens the crimp allowing the wire to be pulled out. It may take a bit of pulling to get the connector off. I get about 75-80% off this way with no cutting of wire.
The other 20-25% [emoji26]