1996 70hp Johnson erratic idle, bogs down trying to increase throttle 90% of the time

[Dbbpeco]

Got 258 v stratos on a trade. Had sat 5 years. Did all normal checks before starting. New gas, cleaned, checked carbs, performed link & sync, compression test, water pump impeller check. All done per factory technical manual. I can get it to idle ok sometimes, but not consistently, on muffs & in the water. Carbs cleaned & inspected 4 different times. Put it in lake twice. Each time it didn't want to idle properly. Had to get on the throttle quick or it would die. Even then, it doesn't want to increase past a very fast idle. Bogs down if you increase throttle. Decided to idle around just to run engine. Acts like it wants to go once in a while. Sometimes it will increase rpm's, sometimes it'll go ahead & climb. Today, after triple checking everything, put it in again. Got it up finally, and just rode for 25-35 min. Only ran smooth at 3/4 throttle. At full throttle, it would rev up & down like it was starved for fuel, running dry, and picking back up. Ran really good at 3/4. About 26mph. Squeezing primer bulb didn't give any definitive results. Readjusted floats to increase fuel in bowl & fuel flow, and it never would increase throttle after that. Just put it back on the trailer. At my wits end trying to figure this out. Gonna go ahead & replace all of the fuel lines to the motor to rule out any possible air leaks. Any ideas or opinions appreciated.

 

[Dbbpeco]

J70TLEDA is the model number.

 

[Bosunsmate]

have you checked sparks consistent and on all cylinders jumping 7/16gap?
what timing was it idling at in lync and sync?

 

[Bosunsmate]

what colour are your spark plugs?

 

[Dbbpeco]

Spark is fine. Don't have a timing light to put on it. We've tried fine tuning the idle point w/timing block adjustment screw, but it isn't a matter of rpm's as much as a smoother idle that will keep engine from dying out. Still seems to be a fuel delivery issue so gonna replace all fuel lines, rebuild carbs & fuel pump first. Should be done by this time next week.

 

[Dbbpeco]

Ok. Put in 3 carb kits, fuel pump kit, all new hoses. No air in filter. Tested rectifier & stator to the best of my ability with the meter I had. Both seem fine. Tachometer quit so that had me worried about stator & rectifier. 12 volts going to tach, but needle is over around 6000 and doesn't move. Tried pulling signal straight from stator, but still nothing. Long story short, SAME PROBLEM!!!!! Ran fine on muffs right after putting on kits. Put it in the water today. Fires up, idles 8-15 seconds and dies. Fires back up & dies again. Try to give it throttle after starting & it bogs & dies. Revved fine the other day after putting on kits. Held the bulb in case fuel pump kit wasn't working, but made no difference. Pulled the plugs. All three looked the same. Seemed pretty oily to me. Not sure what there supposed to look like, though. I'd call them wet for sure. WHAT AM I MISSING????????? Bout to go crazy

 

[Bosunsmate]

Oily plugs might be from poor spark, bad vro or bad floats. They should not look oily they should look light tannish
so:
Have you checked all sparks with a spark tester 7/16 gap?
Are you running premix or have you a vro?
Is the priming bulb holding firm with engine off

 

[Dbbpeco]

Haven't tested with a gap tester, just pulled the plug & verified strong blue spark on plug. Definitely not tan. Definitely oily/wet. Not running VRO. Using 50:1 premix with sea foam. Before tach quit voltmeter was reading 14 volts or a little higher. Now it only shows 12-13. My meter reads 12 with engine off, 13 running. No decimals on this meter. Rectifier tested continuity on all 3 terminals, swapped leads on meter, and nothing in this direction. Leads me to believe it's good, right? Stator had continuity between leads but none to ground. Tested with different meter & ohms were within spec. Tach dropping out & drop in voltage leads me to think electrical, especially if spark seems weak. What could be the cause & how to test?

 

[Dbbpeco]

Yes. Bulb holding firm with engine off.

 

[pn]

does the compression check out, apologize if i missed that, try disconnecting your emergency kill circuit

 

[Dbbpeco]

Compression was fine on all 3 cylinders. The emergency kill circuit was already disconnected when I got it.

 

[Dbbpeco]

???

 

[pn]

does the prop spin freely in neutral, maybe something binding....try blowing out your pulse line off the vro, then next cheapest step is new coils.

 

[Dbbpeco]

Prop spins fine. Nothing binding. Replaced pulse line to fuel pump. Thinking power pack if anything electrical. It's at the mechanic now. Guess we'll find out soon. Don't want start buying parts just hoping for a fix. Ready for it to be done!

 

[Dbbpeco]

Ok. Got it back from the shop. Even after going through the carbs 4-5 times & putting in carb kits & fuel pump kit, mechanic said only one idle circuit was open. Other 2 completely stopped up. Hard to argue since it's running now. His philosophy is that if you don't soak overnight in carb cleaning solution, you haven't done anything. We used no telling how much spray carb cleaner & copper wire on passages. Ran for him, not for us. Can't argue. Also said linkage wasn't just right(knew that already), and choke wasn't working. He didn't say why, but didn't replace any parts. Moral of the story & the expensive lesson learned? Spend $18 for carb dip before having to put out $270 for a carb cleaning and link & sync!!!! At least I got to take my girl out yesterday.

 

[btravlin2]

"His philosophy is that if you don't soak overnight in carb cleaning solution, you haven't done anything. We used no telling how much spray carb cleaner & copper wire on passages."

I was beginning to think this was the problem all along. A can of spray can't compete with a dip. Dipping a sitting carb is fundamental. But I believe the book only calls for 30 mins or so, because of potential damage to anything plastic that might be in there.