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Boat wont start 35hp 2 stroke, one cylinder dead

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bc261

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As title states my boat wont start. I'm not sure of the year but I believe it is a late 70's model. S/N is A122741. It is a 2 cylinder 2 stroke. I have done some minor testing and it seems that my top cylinder is not getting any spark. This boat worked fine about 6 days ago, and now it will not start. It seems like it wants to, has plenty of juice. Through my research I believe the switch box to be the culprit, but wanted to get some opinions first, as well as some troubleshooting tips. I would greatly appreciate any advice from you guys figuring this out.

Thanks!
 
I found today a small pinhole leak in the fuel line. I was so happy I thought i had found my problem. Unfortunately it made no difference. I tested the spark plug wires with a plug in light inline tester and only the bottom wire is getting any power. I don't know how I can tell if this is the coil or the switch box. I also checked the float on the carb to make sure that wasn't stuck and it is fine.
 
I have performed most of the troubleshooting tests that I have been able to find online, mostly through CDI. The only tests I can perform are the OHM tests though because I don't have a DVA meter. I would really rather not purchase one on top of the cost of the parts I'm looking at. I now believe after the testing that I may have an issue with the stator or the switchbox.

Does anybody have any opinion on what I should do? I'm about to put on both to just be done with it.
 
Try swapping the leads to the coils (make a wiring diagram FIRST or you'll go nuts) and see if the problem follows to the other cylinder. If so, replace the coil. Seen a lot of bad ones lately.

Jeff
 
fastjeff said:
Try swapping the leads to the coils (make a wiring diagram FIRST or you'll go nuts) and see if the problem follows to the other cylinder. If so, replace the coil. Seen a lot of bad ones lately.

Jeff
Click to expand...

I swapped the green wires at the switch box that lead to the coils and the problem stayed with the same side. This is what leads me to believe possibly switchbox.

Edit: I'm a little confused. If I take the wire that is powering the coil (Coil #1) and put it on the other coil (#2) and now the other one does not have power that indicates an issue not related to the coil correct?The problem stays with the lead.
 
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Feel like I'm writing to myself here but at least I have a record for what symptoms are occurring and how I'm getting them fixed for the next guy who comes along and needs a hand.

Today I found an eBay listing for a used CDI switchbox and 2 coils for under a hundred dollars. Considering I am eliminating 2 of the possible issues with these (granted, used could be d.o.a, but he's got a great rating) and I am almost positive the issue is the switchbox. To Fastjeff, i've found multiple threads which sound similar to my issues and you've replied on most that this was likely the culprit. I am crossing my fingers

In the meantime I think I want to clean up my wiring and clean the carbs while I'm at it. I am also wondering how difficult it would be to install a push button starter?
 
The problem is finding a starter. Does your flywheel have the gear teeth on it? (I recall they all did.)

You DON'T need the charging system, for even a small motorcycle battery will start it 30-40 times.

Jeff
 
fastjeff said:
The problem is finding a starter. Does your flywheel have the gear teeth on it? (I recall they all did.)

You DON'T need the charging system, for even a small motorcycle battery will start it 30-40 times.

Jeff
Click to expand...

Yes it does have the teeth all around the bottom of the flywheel. Why would I need a different starter? If it's not possible to switch easily then i'm not going to worry about it. I just broke the house for my ignition while doing all this testing, and thought it would be a nice replacement. I also just realized that i do have the push to choke, and that would have to exist still. I'll probably just order a new ignition. They're not too pricey really.
 
I've ordered a used CDI switchbox from a good reputable dealer on ebay and he is sending me 2 coils as well. He said he's tested each of the parts and they are in good working condition. I got all the parts for about what a single coil would have cost me new, so I figured I might as well. I've been waiting several days for it to arrive and it's been torture.

In the meantime I decided to completely tear down the carburetor, which did have some signs of debris but nothing major. I installed an extra disposable paper fuel filter just before the quick connect at the motor.I checked the fuel pick up in the tank for crud and it's spotless. I was going to purchase new fuel bulb and line, but they are both in good enough condition until they give me an issue. I also inspected all of the wiring harness on the motor side, and did find some corrosion on the factory connections. I decided to go through and re-splice all the connections while there. I found that the thread connection at the starter solenoid was a bit stripped and corrected that by adding a few small washers and have a much tighter connection there as well now.

I feel like at this point I've eliminated most possible minor issues that could arise (crosses fingers.) I will update the post when box arrives. Hopefully from my phone out on the water!


Fastjeff, do you know what the brown wire in the harness would be for? I found one that was clipped and tucked in and taped up in there when I redid it.
 
fastjeff said:
Choke?

Jeff
Click to expand...

I believe it is a wire to install a temp gauge wired into the harness, but not used on my model.



I called UPS today because after 9 days of waiting for a part that was supposed to arrive in 3, it's still sitting in another state. They are opening an investigation that can take up to 8 more days. This sucks.

Anybody have a post style switch box they could sell me?!
 
bc261 said:
I believe it is a wire to install a temp gauge wired into the harness, but not used on my model.



I called UPS today because after 9 days of waiting for a part that was supposed to arrive in 3, it's still sitting in another state. They are opening an investigation that can take up to 8 more days. This sucks.

Anybody have a post style switch box they could sell me?!
Click to expand...



I just wanted to update this post for any body out there who finds this and is looking for a solution.

After receiving a new CDI switchbox she started up first try. Running great!

IF you are trying to troubleshoot your no start, PLEASE call CDI. I called and the man on the phone walked me through everything and helped me narrow it down to one or two possibilities. I started with the switch box and it was right.
 
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