any outboard motor guru's ? no spark

[rfuerst911sc]

New to me 1987 Johnson 30 hp outboard. Pulled the two plugs and had the wife turn the key, motor spins great no spark on either plug. Tried new plugs still nothing. Where to start on the diagnosis ? I double checked the throttle control and I don't see any place for a safety lanyard so I don't think that's it. Help please

[Nostril Cheese]

Well, it's either got a coil or magneto. look for it.

[ckelly78z]

Yea, check for voltage coming from the coil/magneto. Clean all electrical connections to fix a possible grounding problem. Check the ignition key switch for having all wires in thier proper place, and corrosion free.

[Radioactive]

I'm a merc guy, but you could check safety-kill switch
could be the power pack

you should probably get a book and meter and start checking resistance per the manual, you need a special meter for checking the high voltage coming out of the stator while its turning.

[rfuerst911sc]

Well it turns out I didn't have spark because I didn't have the safety lanyard. Didn't come with the boat when I bought it. Went to local marine store and bought one. Now I have a strong spark but she won't stay running. She will run for 2-3 seconds then die. So I either have a carb problem or a fuel pump problem or a combination of both. But at least she has good spark. I'll rebuild the carb and see if the fuel pump has a diaphragm that may be ruptured. I'm close to having her running.

[intakexhaust]

OK... lanyard switch... check. LOL. Better check if you have the drain plug in too!

Starting fresh? If possible, drain all fuel, flush lines, carb bowls. After you service, rebuild or whatever in the fuel circuit and if still fails to run, check the condition of the reeds.

Also, fuel today is a big issue with older two strokes (and depending what part of the country your in) so after you get it running, check the spark plugs for proper coloring - lean / rich fuel mixture. One more thing.... make sure its pumping water.

[ckelly78z]

If it runs for 2-3 seconds, take the carb apart and spray gumout/carb cleaner through all the small metering holes, jets, and pickup holes to get any varnish out.

[rfuerst911sc]

I have already serviced the water pump with a new impellar and housing. I need to study the repair manual to see how the carb comes off, it looks like the starter has to be removed to get to the one mounting bolt. I'll try starting her a couple times today to see what happens, maybe fuel sitting in the carb over night did some good. And yes I do have the transom plugs.

[drcoastline]

How old is the fuel line and bulb? If there is a crack allowing air into the fuel line the engine won't stay running. Check the clamps around the connection points also to ensure they are tight.

[rfuerst911sc]

Originally Posted by drcoastline

How old is the fuel line and bulb? If there is a crack allowing air into the fuel line the engine won't stay running. Check the clamps around the connection points also to ensure they are tight.

Fuel line and primer bulb are brand new and I used fuel injection clamps at every connection. I have no visible leaks and don't smell anything. When I pump the primer bulb you can feel the fuel moving and it does get hard so I believe all is working well. But after the 2-3 second run times I have to prime again or at least that's what I have been doing. Also the connection at the engine is a new piece . I double checked the fuel tank vent and it is open, it is a turn screw that can be open or closed it is fully open. I even tried cracking open the gas cap that made no difference. I need to understand how the fuel pump works, it either isn't drawing the fuel or the carb is not allowing it to be drawn.

[john70t]

Check/replace fuel lines if any cracking on the inside.

Had an outboard that began running poorly.
Outside of lines looked fine.
Inside, small bb's of rubber were getting pulled into the carb mixture. That can't be good.

[rfuerst911sc]

Fuel line from the portable tank to the engine is two weeks old with a brand new primer bulb.

[johnco]

if I remember correctly, those old motors used a vacuum operated fuel pump. check the diaphram in the fuel pump for cracks/dryrot. pumping the bulb fills the bowl which runs dry if the fuel pump isn't filling it and motor dies. runs again when you fill the bowl with squeeze bulb right?
old trick I used to use was to put the fuel tank higher than the carbs and let it gravity feed. if it keeps running, then you have a vacuumleak/fuel pump issue

[drcoastline]

Originally Posted by johnco

if I remember correctly, those old motors used a vacuum operated fuel pump. check the diaphram in the fuel pump for cracks/dryrot. pumping the bulb fills the bowl which runs dry if the fuel pump isn't filling it and motor dies. runs again when you fill the bowl with squeeze bulb right?
old trick I used to use was to put the fuel tank higher than the carbs and let it gravity feed. if it keeps running, then you have a vacuumleak/fuel pump issue

Exactly, before you go into all the other issues make sure there isn't a vacuum leak. Double check the connections, the lines, the bulb. How is the connection between the fuel line and the tank made? Hard connection or the spring loaded connection like the photo? If it's like the photo they are notorious for leaking. Make sure your connections are secure before you start tearing you motor apart.

[johnco]

I would think that if you pressurize the system with the squeeze bulb and find no fuel leaks, then you probably don't have vacuum leaks. one screw holds the fuel pump together I think, easy to check. going by memory of course. used to work in a outboard repair shop in the 70's. my only recent experience is that I just got a 25 mecury running after sitting for 15 yrs in my back yard and froze up for 7 yrs before I got it.