| Author |
Message |
    
Dale Mason
New member
Username: benji0301
Post Number: 2
Registered: 08-2009
| | Posted on Monday, October 26, 2009 - 06:12 pm: | 
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Hi All,
I purchased a 2nd hand Mercury model 35 35HP about a year ago which I saw running on the previous boat and have just go round to fitting it on my own.
When trying to start it though I get a vicious recoil from manual start cable that nearly rips my arm out of its socket. I have checked that I have a good spark and know that its not in gear so would like to know any ideas.
If i press the stop button on the side of the engine i don't get the recoil but as soon as I release it and try to manually start it kicks back.
I haven't played about with the timing in any way so wanted to know if there is some kind of safety switch that I have activated?
My friend seems to think that the cylinders are firing before it reaches TDC pushing the piston back down and thats why i'm getting the recoil?
Is is a Mercury Model 35 2 stroke 35HP, serial number 9408207, Manual start model.
Any ideas??
Benji |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 7009
Registered: 09-2003
| | Posted on Monday, October 26, 2009 - 06:38 pm: |
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I'll bet you a six pack the plug wires are reversed!
Jeff |
JB
Senior Member
Username: beckerjs
Post Number: 2026
Registered: 11-2005
| | Posted on Monday, October 26, 2009 - 06:59 pm: |
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On my 35hp the plug wires cant be reversed because the wires are to short. But if someone messed with the switchbox wires, mmmmmm |
Dale Mason
New member
Username: benji0301
Post Number: 3
Registered: 08-2009
| | Posted on Monday, October 26, 2009 - 08:00 pm: |
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Definately can't get the plug wires the wrong way round as one is a lot shorter than the other, switchbox wires??? Where are they? |
JB
Senior Member
Username: beckerjs
Post Number: 2028
Registered: 11-2005
| | Posted on Monday, October 26, 2009 - 08:59 pm: |
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if you follow the coil wires they lead back to the switch box. I doughty this is the problem unless someone has been playing with it. It should start with the timing at 3-5 btdc, but if something is not right and you are advancing the throttle it can change the timing up to 27 degrees before tdc, causing a hard kickback
and I'm on for that 6-pack Jeff, but I'll share |
Dale Mason
Member
Username: benji0301
Post Number: 4
Registered: 08-2009
| | Posted on Wednesday, October 28, 2009 - 03:46 pm: |
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Hi guys,
Had an engineer round today and it was a combination of 2 things:
1. when I serviced the carb I didn't adjust the float correctly which subsequently sent to much fuel flooding the carb.
2. There was no spark on cylinder 2 which was leading to filling of fuel in cylinder & hydraulic lock
He checked the plugs, leads & coils which are all ok so he says its either Switchbox/CDI, Stator or Trigger assembly. He unfortunately didn't have the tools to check them but is coming back tommorow to test.
So its going to cost me either £110 for Stator, £52 for trigger or £85 for switcbox and obviously labour on top so probably another £150
I am a reasonable mechanic, are any of these things beyond me to fit myself? The switchbox looks like bolt, but not sure whether I should tackle removing pull start assembly?
Advice would be appreciated. |
JB
Senior Member
Username: beckerjs
Post Number: 2030
Registered: 11-2005
| | Posted on Wednesday, October 28, 2009 - 05:00 pm: |
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switch box is easy, the hardest part of the trigger/stator is getting the flywheel off. The good news is its almost always the switch box. You can test the others without removal, the procedure and specs can be downloaded here. Located in the troubleshooting and dva specs
http://cdielectronics.com/Downloads/tabid/55/language/en-US/Default.aspx
You never said what year so thats all I can help with. If I'm a shade tree mechanic does that make me an engineer? |
Dale Mason
Member
Username: benji0301
Post Number: 5
Registered: 08-2009
| | Posted on Wednesday, October 28, 2009 - 06:01 pm: |
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Cheers JB
I beleive its a 1984 model but not 100% sure because all i've got is the serial number 9408207 and the manual that came with the engine was printed in 1983. Why would the switch work on one plug but not the other? Anyway as its one of the cheaper parts i hope you're right.
Cheers
Benji |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 7031
Registered: 09-2003
| | Posted on Wednesday, October 28, 2009 - 06:44 pm: |
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.."Why would the switch work on one plug but not the other?"
There's two separate circuits in there (on yours). I have one if yours is a big, ugly aluminum box with wires coming out. (There's also a black plasic box with or without screw terminals.)
Jeff |
ian summerfield
Member
Username: budgie14
Post Number: 74
Registered: 06-2009
| | Posted on Monday, November 02, 2009 - 05:26 pm: |
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Question,if the switch boxes look the same on two different merc engines[one 82 18hp other 97 15hp]any chance they are the same.black plastic box.would faulty switch box cause backfire?thanks in advance |
Fastjeff
Senior Member
Username: fastjeff
Post Number: 7072
Registered: 09-2003
| | Posted on Tuesday, November 03, 2009 - 06:08 am: |
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I've mixed and matched several of those years. Be careful on the wiring up: they used different color codes at times. Take your time and be logical.
Jeff |
