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Charles
Charles, Marine Mechanic
Category: Boat
Satisfied Customers: 3976
Experience:  US Navy (Ret) Certified Mercury Marine Tech with over a decade of repair experience.
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Im having trouble with me 2005 byliner 195 fish/ski boat. I

Customer Question

hi
JA: Hello. How can I help?
Customer: Im having trouble with me 2005 byliner 195 fish/ski boat. I have a 3.0L mercruser and there is no spark. There is two wires running down the back of the engine into the leg; and if I wiggle those the engine fires up. I'm not sure what its attached to and can't seem to find a wiring diagram that tells me.
JA: Sometimes boat issues seem like they'll be really complicated, but end up being easy to fix. The Marine Mechanic I'm going to connect you with knows all the tricks and shortcuts. Is there anything else important you think the Marine Mechanic should know?
Customer: I changed the shift interrupter switch as I thought that might be it.
Submitted: 2 months ago.
Category: Boat
Expert:  Charles replied 2 months ago.

Hello, my name is***** will assist you.

Expert:  Charles replied 2 months ago.

The only two wires that run from the engine to the outdrive are for the trim gauge and the trailer switch. Trace them back onto the engine to where they plug in, unplug them and then see if the engine will start. If it does, there is either an issue with the engine harness or the trim sender on the drive.

Customer: replied 2 months ago.
All I need to do is wiggle them were they go into the leg and it fires; also as I move them they cause the engine to quit. Ive unplugged them and put them together, but it doesn't fire.
Expert:  Charles replied 2 months ago.

Are you sure that they go thru the transom and not going to the distributor on the rear of the engine?

Customer: replied 2 months ago.
Ive moved the leg up and down and it will start, or moved the steering wheel from side ti side and it starts as well. Im sure its got to do something with whats in the leg.
Expert:  Charles replied 2 months ago.

What color are these wires?

Also, do you have the serial number of the engine and the drive?

Customer: replied 2 months ago.
positive about were they go. Its two wire that come up the back of the engine and plug into the wiring harness.
Customer: replied 2 months ago.
they are black wires
Customer: replied 2 months ago.
the engine serial # is ow602090
the transom # is 0w485247
Expert:  Charles replied 2 months ago.

Do the wires look like the ones in this pic on this page if you blow it up?

http://www.shop.tungstenmarine.com/Trim-Sender-and-Limit-Kit-for-Most-Mercruiser-Stern-Drives-TM7633.htm

Customer: replied 2 months ago.
they kind of do. The connectors are the same for sure.
Expert:  Charles replied 2 months ago.

Does the trim gauge in the boat work?

Customer: replied 2 months ago.
it does
Expert:  Charles replied 2 months ago.

Odd, those wires really only go thru the harness to the dash and one goes to the trim to stop the tilt and have you hit the trailer button.

Try to unplug all 4 or 2 depending on the set up, just tape them off so they do not ground against the block and see if the engine will start.

Customer: replied 2 months ago.
sorry, yes the trim gauge seems to work fine. The wires look close but the connectors are the same for sure.
Expert:  Charles replied 2 months ago.

The connector is the standard one that Mercury uses for most of its connections that it wants to keep water tight.

Customer: replied 2 months ago.
Why would the trim sender kill the engine? I mean it looks like the wires, but just not sure how it works?
Customer: replied 2 months ago.
Like you previously mentioned; if I disconnect the wires will that the the switch out of the picture and allow it to start.
Expert:  Charles replied 2 months ago.

Theyt should not, that is what is making this so confusing. Those wires have to be going into the harness and coming out somewhere else.

Customer: replied 2 months ago.
Will that take the switch out of the picture and allow the engine to start?
Expert:  Charles replied 2 months ago.

That did work? With the trim senders unplugged the engine started?

Customer: replied 2 months ago.
How does that switch not allow spark to the engine?
Expert:  Charles replied 2 months ago.

Try leaving the trim wires plugged in, but disconnect the trim gauge. The purple and the black from it. The purple will be hot when the key is turned on and the black is a grond, so dont let them touch.

Expert:  Charles replied 2 months ago.

There has to be another cause down stream. Try that with the gauge.

Customer: replied 2 months ago.
ok will do. Ill have to try it in the morning.
Thank
Expert:  Charles replied 2 months ago.

Also keep in mind that the shift interrupt switch uses the same type of connectors, and only has 2 wires.

With a multimeter we can test it to see if it is working correctly

Expert:  Charles replied 2 months ago.

I should log on around 10 or 11 AM CST. Depends on how late I fall asleep tonight.

Customer: replied 2 months ago.
how do I get ahold of you tomorrow/ Im new to this.
Expert:  Charles replied 2 months ago.

Just reply back to this thread and it will come straight to me. Either bookmark the page or remember your log in info.

Customer: replied 2 months ago.
Ok thanx
Expert:  Charles replied 2 months ago.

We do the site from out homes, so there is no set time to "get to work" and I do stay on here late to assist the late night customers like yourself.

Customer: replied 2 months ago.
hi charles
Ive tried unhooking everything that you said and it still quite and will not start. How do I check the ignition components ( coil, pickup coil and module)?
Expert:  Charles replied 2 months ago.

unplug that shift interrupt switch and see if it will crank over. It is designed to stop the engine for just a split second when shifting. Do not connect the wires together, just leave then apart.

Customer: replied 2 months ago.
ok I've figure something out. If I plug a jumper wire from the battery to the coil it works with no issues. Ive wired a volt meter into the purple positive wire going to the coil. What I notice happening is; the voltage goes from 12 volts to 14 (when its running ) then it suddenly drops to 10v then 9, then 8 and the engine quites. sometimes it goes from 14v to 0v . Could that be the ignition switch? Ive moved the wires at the ignition switch but it doesn't seem to make a differance.
Expert:  Charles replied 2 months ago.

Great test there. Measure the voltage like that again, this time on the red of the key switch. If that is good, move to the purple and see if it falls off. If it does, replace the key switch. If it does not, the issue will be in the harness on the engine