1978 500/50 hp timing.

[supreme]

Hey everyone, I install a new trigger and switch box. I am getting great spark now. I went threw the carbs, I still can't get it to start. I get a single pop out of it. So I thinking it may be the timing. When I placed the flywheel back on I made sure that I line the timing mark to the pointer and TBC. Now when I place the timing light on it and turn it over it doesn't come into the mark at all. It comes in about a 1/4 turn rotation of the flywheel retarded side and when I place the timing light on the 4th cylinder it reads close to TBC. Did I wire the switch box wrong or what? I replaced the trigger and the wires are a little different then the old one. They did not have a black with white stripe one, it was just black. So I placed it on the black and white terminal on the switch box. Is that right? If someone haves some thoughts on this please let me know. Many thanks

San Diego
Devin

 

[Smig]

Re: 1978 500/50 hp timing.

Devin,
Until someone with a bit more experience comes along...I can't address the wiring question, but do have a suggestion in the meantime.

Did you check the timing via the process described in the FAQ? One of the steps is verifying TDC in Cyl#1. I had a similar experience and found that the flywheel was in the incorrect position.

Here is the link to Clams' thread. Setting TDC is approx 75 posts in:
http://forums.iboats.com/showthread.php?t=128495

Shaun

 

[supreme]

Re: 1978 500/50 hp timing.

Shaun, thanks for the info. I checked the TDC and it's fine. Pulled the #1 plug checked cylinder position and lined up TDC on the flywheel it's simple. Place the light on #1 cylinder and crank it over. Can not get it to line up to TDC when cranking. Does the motor need to be running to get that result? I checked out the link you sent it good. It better than the manual I have.

Many thanks
Devin

 

[Smig]

Re: 1978 500/50 hp timing.

Now you're getting a bit beyond my experience - the only other timing thing I can suggest would be to check your spark advance lever. Since you probably have everything disconnected make sure they are all back where they belong.

You might also want to check your flywheel again - I'm pretty sure it is two pieces, the hub (that is attached to the hub by the flywheel nut) and the flywheel plate itself which is bolted by to the hub by a ring of bolts. Make sure the hub is properly indexed on the crank and then check the flywheel against TDC. It is possible, if the ring of bolts where removed, for the flywheel plate to put back in the wrong position - that could change the relationship between the timing marks and pistons. Sorry if this is confusing, but try a search - I know someone out there has explained it better.

Other than that, you need someone with more experience than I...sorry.