'55 7.5 Evirude no spark

[HighTrim]

Re: '55 7.5 Evirude no spark

Graphite core wire is used to suppress EMI and RFI noise. This noise can send false signals to the ECM (computer). This is important in newer cars. It also has another advantage which tempts many outboard enthusiasts, its cheap.

Why cant we use it? For one reason, it has a high resisitance which reduces the spark current, which is what reduces the noise actually.

Dont be tempted into the graphite core wire.

 

[HighTrim]

Re: '55 7.5 Evirude no spark

I forgot the main reason as I got sidetracked, the excess resistance will cause burn out of the secondary winding in the coil!

No magneto ignition should use this wire.

 

[CreekRunner]

Re: '55 7.5 Evirude no spark

OK guys! Carb parts due in tomorrow or next day. Assuming all goes well on carb rebuild, I'm going to do the lower end. What are areas of concern there? I know impeller. Any thing else other that new gaskets etc.?

Hope to get her running in the next couple weeks. The Crappie are biting and the stripe start running next month.

Thanks,
David

 

[HighTrim]

Re: '55 7.5 Evirude no spark

Have you checked the gear oil? Is it milky white or black? If there is water intrusion you can tackle the gearcase reseal now. If not I would leave it and just do the impeller.

Dont forget to pay attention to the lower crank seal as mentioned above.

 

[CreekRunner]

Re: '55 7.5 Evirude no spark

Will do ! Thanks Chris.

 

[AlTn]

Re: '55 7.5 Evirude no spark

do a search on youtube as someone has done a vid on removing the powerhead to replace the impeller on a 7.5

 

[kfa4303]

Re: '55 7.5 Evirude no spark

I think this is the vid.

http://www.youtube.com/watch?v=SVOedhzPP7M

 

[CreekRunner]

Re: '55 7.5 Evirude no spark

Thanks guys, I've actually seen that video I think.

Back to the carb. Parts came in today. Taking apart and soaking the old carb body. Took a couple of screwdriver slotted plugs and barbed connector where gas line comes in off earlier. Do these need any pipe compound or teflon tape on threads? How about internal parts that I havn't got to yet?

Thanks

 

[kfa4303]

Re: '55 7.5 Evirude no spark

Nope. No teflon tape or pipe dope needed. Just make sure everything is squeeky clean. Here's a hand link for rebuilding a similar carb.

http://www.outboard-boat-motor-repa...hnson 5.5 HP 1954-1964 Carburetor Tune-UP.htm

 

[CreekRunner]

Re: '55 7.5 Evirude no spark

Got my carb parts and put back together for the most part. Can't seem to get the throttle valve to turn freely inside the throat. Had to put a new throttle shaft in. Everything seems to be lined up right. Can I file, trim the throttle valve a little? Or any other ideas?

 

[kbait]

Re: '55 7.5 Evirude no spark

Remove the valve part itself and make sure the shaft turns freely. If it does, sounds like you may have to either center that plate better, or modify it if it's rubbing in the carb throat.. Good luck!

 

[CreekRunner]

Re: '55 7.5 Evirude no spark

Hey kbait. Yea, the shaft turns fine by itself but with valve installed I can't get it lined up or something and it binds inside the throat. I will keep trying though.
David

 

[jay_merrill]

Re: '55 7.5 Evirude no spark

Graphite core wire is used to suppress EMI and RFI noise. This noise can send false signals to the ECM (computer). This is important in newer cars. It also has another advantage which tempts many outboard enthusiasts, its cheap.

Why cant we use it? For one reason, it has a high resisitance which reduces the spark current, which is what reduces the noise actually..

HT, I've been running them for a long time with no problem. Based on comments that I've seen, I think the fear of them comes from the old battery CD type ignition systems, which were not particularly hot to begin with.