replaced everything and wont run on 3 cylinders proply

[grub_ba76]

i im new and need help badly......i recently bought 2 dt65 93 models of my dad for $500....he has had em since new....never worked hard or reved hard and does not have many hours on them.(20 mins each fishing trip)...they were really sick win i got them...i replaced fuel pumps, rebuild carbs,sync throttles, replaced all fuel lines from tank too motor,new fuel conections,new water sep filters.flushed out oil injection and put new castrol in...one motor is running excelent...the other wont idle on all 3 cylinders .when under load it will go ok but hasnt got the power as the other one has...it will idle on 3 cylinders but roughly and cuts in and out from 2 to 3 and wont rev hard...top cylinder compression is 130psi middle 115 bottom 130..ive check compression 3 times over a period of 3 months...top spark plug is black middle and bottom are wet with fuel and clean.(new spark plugs got em 3 days ago)ive checked coils ect..i pulled carbs apart again to check...on the grass where im running engine theres black oil all over grass.(the patch is the size of a car wheel)....im thinking its black cause its not burning the fuel...smokes alot too even when warm...smokes the same if hot or cold....smoke seems to much to me......cause i was standing near the motor when running and i got wet from water spray. now my clothes smell badly of fuel....when i pulled carbs down i reset floats too 16 mm instead of 17mm incase it was getting too much fuel.(correct me on this if its bad)...when running it at say 3000, 4000 rpm it seens to run on all cylinders but is weak in power like its flooded....tanks were flushed and replaced with good fuel...no air leaks...getting plenty of fuel....if i disconect fuel line once it starts to run out of fuel it seems to run on 3 cylinders good (but only somtimes)and revs hard....put fuel line back on pump fuel pulp and it gos back to 2 cylinders....too me its getting to much fuel....the plugs are very wet when i pull em out....if i clean and dry them it seems to run on 3 cylinders better but only for 5 mins....ive got the suzuki work shop manual...please help...thanks graham

 

[James R]

Re: replaced everything and wont run on 3 cylinders proply

Most probably the top cylinder is running rich due to a leaking needle valve.
Replace the seat and needle valve and you should be ok.

 

[grub_ba76]

Re: replaced everything and wont run on 3 cylinders proply

all carbs have been rebuild(new needle and seats) motor was running bad when i got it all these thing have changed nothing....it seems to be only fireing on top cylinder..if i disconnest the linkage on the chokes and close one at a time ....when i close top one motor wants to stall(cause its getting to much fuel) but when i close middle and bottom it doesnt to much to the motor at all.....im playing with it now it seems to be getting worse now im having troubles starting it....thanks graham oh and ive pulled the carbs apart to check and its only done about 10 mins since ive done all this work...

 

[Dunaruna]

Re: replaced everything and wont run on 3 cylinders proply

check you coils secondary circuits (the spark wires). The spark may sound and look o/k but it needs to be a big blue 'snap' to light the fire under load.

The stain on your grass is unburned fuel, no burn means no bang.

 

[grub_ba76]

Re: replaced everything and wont run on 3 cylinders proply

yep thats what i thinking but......i have 2 of these motors on the boat all coils on both motors are reading the same......i put new spark plugs in this motor and only ran it for 20 mins and it got worse the longer i ran it and then wouldnt start at all so i swaped all spark plugs over from other motor and it ran on 3 cylinders and missing on one but ran better like it origanly was....so now i worked out the plugs a stuffing up quickly(br8hs as it says to use)its still smoking real bad and pours out when reving a little...i disconnected the link from carb to injection pump but smoke didnt change...and its either running way to rich or not sparking proply which makes the grass black....as i said rebuild all carbs and reject them a second time...if i squeeze the pulp u can here fuel flow in then stop and pulp goes stiff(telling me carbs are full and needle and seat is working) would out of timming make it look like its running rich or foul plugs....could there be big props with one of carbs.....im no expert ....but i disconnected the throotle linkages and when i open just top carby(to make it rev)it dont smoke and doesnt want to rev...when i do middle one it smokes alot and will rev good...bootom one same as top....is this cause of middle carb having throttle sensor or is that my proplem there with it smoking alot.....im stating to think 1 to much oil 2 to much fuel ....which would mean the new needle and seat are faulty or fuel pump is faulty.......thanks for helping....graham

 

[grub_ba76]

Re: replaced everything and wont run on 3 cylinders proply

how can 3 spark plugs stuff up so quick and have no spark they only lasted about half hour