always check for loose wires and hoses too, especially if it has just been put together
cheers
I'm thinking it might be your floats, it would explain some of the symptoms your having,
if they are low it will cause the harder starting and the starving at the higher revs when it needs more fuel or, maybe the needle and seat sticking, and if you get that far it would be best to give the carbs a good clean, good luck
always check for loose wires and hoses too, especially if it has just been put together
cheers
Same thing happened to me early December,would have bet my left nut it was fuel problem as it was doing exactly as you have described but when Id power up over 1500 revs she would go for about 200 meters then die but I could still cruise around under 1500 revs and it still started perfectly.I had a mechanic look at it first thought it was a power pack but turned out to be the stator not puting out enough spark.Ive got twin 120hp Evinrudes 92 models so very similar if not the same,hope this helps cheers.
Ok my 2 cents worth, Had a old chrysler do this to me once in a very blue moon and it turned out to be the fuel tank connection sucking air. Zip tied the bugger together, never had that problem again.
If the fuel hose has the quick coupla style connector to the engine sometimes the spring inside gets weak and allows the valve to close. Jim
Haines Signature "FinaLeigh" 580F 135 Optimax
CH 81 & 72 VHF
Check the entire fuel system. If there is nuthing that stands out, take it to someone who has a good working knowledge of them.. those 140 are known to have issues which go bang if not repaired correctly.
Garry
Retired Honda Master Tech
Id be guessing High speed side of the stator assy.
Had a similar problem, was the fuel bulb. Does it take more than three pumps to get fuel pressure up. Have been told by many a mechanic that three pumps should do the job unless the motor hasn't been run for awhile. If air is getting in it causes a full or partial air lock. fuel pump on motor vapour locks and can't pump air through system, hence the reason for the bulb to prime everything first. Air may be getting in elsewhere also. As suggested above check the whole fuel system over. If anything suss would replace all fuel line. The only thing I didn't replace was the bulb, turns out it was letting the air in. Start with the bulb first.
OK, if you are still in trouble, heres some easy an almost no cost things to try, get a complete tank and hose with fuel and use it, trouble still there? pump primer bulb when it gives trouble (this basicaly by passes the fuel pump), pull the plugs and have a look at them, are they all the same? do a compression test, all this will take bugger all time and cost nothing, will not introduce a new fault and will give us an insight as to where to head next. Ok with all that? to replace expensive non returnable parts on a "sounds like" will only empty your wallet and may not fix anything. Also get a genuine manual for your model, it will pay for itself on the first day!
Does sound like fuel supply somewhere/somehow, air leak, poor pump, vacume, blockage......a hose full of raw oil (how smoky was it?)
cheers fnq
Everyone knows of somebody who spent a small fortune before the mechanic found it was a $2 part. Try pressurising the fuel line (primer bulb) and wriggling the joints. Less pressure in line when running may mean it ocasionally sucks air. Does any thing leak including carbs. Can breather be removed. Is tank pickup still clean. Try borrowed portable tank strait to motor. I know i always seem to find something that should be replaced even if its not the problem. Back yourself to eliminate the basics everyones already mentioned before demolishing the wallet.
I think that's what I just said??
Slow on the trigger. Something to do with kids and swimming pools.
Yep. Id say air getting in somewhere.. whether around the tank connectors or at the carby. I had similar but who knows.