2003 Yamaha 70hp 2-stroke extra clean, low hours.
Went fishing two weeks ago and ran like a dream, came home and flushed on the hose and put it inside the garage. Always kept inside.
Pulled it out today and won’t crank up. Spins like a top, plugs getting fuel, tons of compression…I bypassed kill switch but still no spark. I hooked my timing light to it and had my son spin it over and the light lit up four or five quick times and then no spark while spinning. Same result on all three plugs. If you spin it for a full minute…it may spark just for an instant, sometimes no spark at all. Help me Chris V or anyone else…how do I backyard mechanic style tell if its the powerpack or stator, rectifier, etc?
I had a similar problem with my 70nasty Johnson. Replaced the plugs and she fired right up
fish today work tomorrow
I have no spark going to the plugs.
Rick
23 Center Console
Twin 140s
“Dirty Money”
Update - I do have plenty of spark at each plug, one of the tester light wires was not on good. Motor is spinning with spark and strong compression and pulled plugs and they look too dry. I opened drain plugs on carb bowls and they had gas in them. What could it be?
How does the choke on this work? It is not a push key, but to choke it, I was always told to spin it over twice and it would then crank on the third try everytime. I do not see a choke solenoid or anything else to manually flip.
Rick
23 Center Console
Twin 140s
“Dirty Money”
I have it running and it appears to be a fuel issue. There is a red lever on my air intake that states “Emergency Fuel Enrichment”, when I open the lever it runs fine, when I close it…it sounds like it is not running on all cylinders. Anyone familiar with this emergency fuel enrichment? Possibly fuel pump or a clogged carb?
Thanks
Rick
Rick
23 Center Console
Twin 140s
“Dirty Money”
Running fine now. Apparently the emergency fuel enrichment just lets gas by the carbs. I knew it was a fuel starvation so I opened the bowl drain plugs again and gas pored out of #2 and #3 but only a few drops outta #1 so i thought float was stuck. Took air hose on very low pressure and blew up into it and tapped on side of carb gently and gas poured out. Went to the key and it busted off and ran strong. probably need to pull that carb and clean it on next free day.
Rick
23 Center Console
Twin 140s
“Dirty Money”
clean those carbs sooner than later. lean is the most deadly condition for piston failure.
clean 'em all. If one is giving you issues. The others aren’t far behind.
17’ Henry O Hornet
26’ Palmer Scott
I have the exact same motor, and had the exact same problem a couple of years ago. I had all 3 carbs cleaned and no problems since.
Motor is running great but I know all about a carb getting plugged up and burning a cylinder. I just checked online and can get the carb kits for $23 each and will be doing all three and a new 10 mic filter. Boat has always been ethanol free.
Thanks for your responses.
Rick
run a can of seafoam through it, and it will probably be fine
sounds like one of the needles was stuck
do a drop cylinder test to make sure its running equally on all 3 cylinders
Thanks Chris, I will run a can through it this weekend.
Rick
23 Center Console
Twin 140s
“Dirty Money”
Chris,
Can you explain a drop cylinder test please?
04’ Scout 185SF / F150
- Turn it off.
- Remove ONE spark plug lead and ground it. <—Place bolt into it and allow it to touch the engine block.
- Restart engine and see if the engine runs any different. If it does run differently, that cyl is most likely working properly and is not the problem.
- Turn it off.
- Replace the spark plug lead and remove a different one.
- Follow the steps above until you isolate the cylinder causing the problem.
It ain’t no mystery…this beer’s history!
we actually pull the plug wire while teh engine is running
use special tool, or you will get shocked