Yamaha Owners : A wiring question

[T Smith]

Ive got a 1999 Yamaha C40TLRX and I need to know where the light blue wire that comes off the prime starter assembly goes.

It is the electronic choke thinga ma jig on the port side of the motor by the carbs. There is a black wire that is grounded and a blue one with a male plug but I can't fine where it should go. Other Yamahas of similar size and year should have a similar setup. Any help would be appreciated as this is the last barrier in taking my recently completed project boat to the water. Apparently this prime starter sprays gas into the carbs when you push in the key choke.

This is how I feel after three days of wiring and unwiring

Oh yea the wiring diagrams in the shop manual I bought are worthless, the whole book is for that matter, nothing but Yamaha Service Manuals from here on out for me..

[Sir reel]

Don't know if this is the correct image but can you identify the wire from this?




Item Part # Description Notes Req
1 6H4-82105-02-00 WIRE HARNESS 1

2 6G1-81941-10-00 STARTER RELAY ASSY 1

3 6H4-81952-00-00 HOLDER, RELAY 1

4 6H4-81945-00-00 PLATE, SWITCH FITTING 1

5 90116-06M22-00 BOLT, STUD 1

6 95380-06600-00 NUT, HEXAGON 2

7 92990-06600-00 WASHER, PLATE 1

8 6H2-81960-00-00 RECTIFIER & REGULATOR ASSY 1

9 6H4-82150-00-00 FUSE HOLDER ASSY 1

10 682-82151-00-00 FUSE (20A) 1

11 97095-06014-00 BOLT 1

12 92990-06600-00 WASHER, PLATE 1

13 90464-15M27-00 CLAMP 1

14 90338-05M11-00 PLUG 2

15 63D-82594-00-00 CLAMP 1

16 97095-06012-00 BOLT 1

17 92990-06600-00 WASHER, PLATE 1

18 6A0-82119-00-00 COVER, LEAD WIRE 1

19 63D-82590-20-00 WIRE HARNESS ASSY PTT 1

20 6H1-81950-00-00 RELAY ASSY PTT 1

21 97095-06025-00 BOLT PTT 2

22 92990-06600-00 WASHER, PLATE PTT 2

23 6H4-81945-20-00 PLATE, SWITCH FITTING PTT 1

24 90480-13M24-00 GROMMET PTT 3

25 90387-06M05-00 COLLAR PTT 3

26 90105-06M15-00 BOLT, WASHER BASED PTT 2

27 90105-06M16-00 BOLT, WASHER BASED PTT 1

28 6H5-81949-00-00 WIRE, LEAD PTT 1

29 6H2-81949-11-00 WIRE, LEAD PTT 1

30 682-82119-01-00 COVER, LEAD WIRE PTT 4

31 6N6-82582-00-00 COVER, WIRE HARNESS 1

32 6H3-82151-00-00 FUSE 1

33 90464-07M20-00 CLAMP 1

34 6H4-82117-00-00 WIRE, LEAD 1


Or is it the leads from item #34 in this image?

[T Smith]

Sir Reel ,


It's Item #34 in the lower diagram. You can see the Negative wire has the bolt and washer that go into it items #44 and 43. The other lead with the male plug that is pointing up in the diagram is the one we can't figure out. We have found a red wire with a female plug but it has constant power and that doesn't seem right if the primer is only supposed to work when the choke is momentarily pushed in. We did hook it up to the red wire and it wouldnt run, but we are thinking maybe we flooded it by having constant juice to the choke.

[Sir reel]

Do you have the ignition switch that pushes in for choke?

[T Smith]

Well I think that might be part of the problem. I just ordered a standard brass ignition switch. It was a three position OFF, ON , START. At first I was under the impression the choke was electrical and automatic. Now I think it is controlled by the key. I have the Yamaha main wiring harness that plugs in at the motor and would normally plug into a yamaha key switch. But we cut the plug off and hard wired the wires to the brass ignition switch. Some wires aren't used but I think they are for gauges that I dont have. I've got spark and the motor cranks but never fires which leaves me to beleive its a fuel issue. Especially since theres that blue wire in the motor thats not hooked up. My gauges and everything work fine. But to eliminate any possibility of the ignition switch being the culprit I have ordered a Yamaha switch (which I should have done from the start, sometimes you just gotta suck it up and pay to do it right). It should be here mid next week. The switch I ordered does have "push to choke" and a kill switch underneath. We are going to rewire the pins in the plug on the main harness and plug it into the new switch. That should eliminate any issues that may be caused by the switch being incorrect or not having choke. Then all I should have to do is figure out that blue wire and she should be fine. So to answer your question. Today I don't have push to choke but next week I should and the switch should be a non-issue next week. This is on that Extreme Flats boat I'm building and everthing has been built from scratch. I bought the motor from a guy who was repowering to a four stroke so It didn't come with any wiring he kept it all on his boat. It's been a saga. My father in law is a mechanic and has built a few hot-rods in his time, but it's even got him frustrated. Again once the new switch comes all we should have to worry about is that blue wire.

[T Smith]

Problem Solved
Thanks for the time Sir Reel , a new Yamaha Ignition switch with the correct wire leads fixed the problem. When all else fails throw more money at it, seems to work most of the time with boats.