followup rough running

[nhdukes]

1996 30 hp evinrude. idles, chugs along.goes good. then on occasion i throttle up and it starts running real rough w/ no power. good gas. first pulled high speed jet and ran and it was better for awhile then it happened. pulled carb and cleaned it looked good. again was ok then it happened. i have a couple questions about this (1) is there no kind of air filter thats bolts on the front of carb? (2) the foam on the inside of cover where the carb is located is chewed up from where it looks like the carb would suck it in. would the carb suck in this foam and clog itself? could i put a lawnmower type air filer there? im gonna pull carb today again and rebuild plus change out all fuel lines. plus i dont see any inline filter anywhere so i will prob add one. this seems to be a fuel prob to me but not 100% sure. thanks for the info

 

[tashasdaddy]

Re: followup rough running

the filter is in the fuel pump. it is a screen. if you remove the center screw, on the pump the round cover comes of what the Orings, the filter is right there.

are you doing this, http://forums.iboats.com/showthread.php?t=244013

 

[nhdukes]

Re: followup rough running

thanks for reply tashasdaddy. i did all of that except soak overnight. cleaned w/ carb cleaner, wire and air. i also cleaned that screen filter. i just thought after all this cleaning and hose replacements a cone inline filter wouldn't hurt. would that foam being sucked in cause this. i am going to run w/out cover on after this to see if it doesn't happen then possibly take foam out of cover. thanks

 

[tashasdaddy]

Re: followup rough running

the problem with running with out cover, is the carbs get too much air, leaning out the fuel mix. you can always take a piece of aluminum screen and secure it or the opening. that is more filter than most outboards have.

 

[nhdukes]

Re: followup rough running

i see. well carb kit didn't arrive today they say tom. i'm gonna run it today and maybe take off carb and soak it overnite. change lines. and hopefully this will cure prob. what should i soak carb in? the stuff @napa is $50 a gallon. a little steep thank you so much

 

[tashasdaddy]

Re: followup rough running

walmart has quart cans.

 

[nhdukes]

Re: followup rough running

thanks again tash. hopefully this will cure my prob. if not we'll chat tom.

 

[Harker]

Re: followup rough running

Change the spark plugs first and see if that helps, get the Champions for it. Are you sure your fuel tank is venting properly? Take that apart and see if the screen on the pickup is plugged with crud and clean the tank if there is junk in it.

 

[nhdukes]

Re: followup rough running

thanks harker i'll try that too. i may just use a whole new ank i have to see if it helps

 

[nhdukes]

Re: followup rough running

alright to anyone who is still in there i rebuilt carbs, changed plugs to champion ql82c,changed fuel lines,cleaned fuel screen, put in an extra inline filter, and bolted on a ss screen to the carb air intake. ran great yest. then it went to crap mode for a minute. i pulled cover and checked to see timing plate was advancing and to see if i could see any problems then the prob cleared up and it was running great w/ cover off. put cover on it was running good then crapola. so i look closely at screen i installed over intake and see tiny bits of foam all over it. i look inside cover and see foam is breaking down due to petro and foam generally dont mix. i have now removed all the foam and glue from engine cover and cleaned bottom of engine compartment of all loose foam and debris and am going to run her today. stay tuned the mystery may be solved..........

 

[nhdukes]

Re: followup rough running

I know this post is old but i wanted to let everyone know what the deal is. I changed powerpack, coil, everything under flywheel, cleaned and rebuilt carbs, changed fuel lines, took out rotten foam from under cover and hmmm, anyway when i changed impellor and cleaned water pump etc. that was the trick. i never had any overheat alarm. I had a solid stream from tel tale and i had a boat mechanic (apparantly not a good one) tell me that the rough running was not slow mode. i also put a radio shack laser thermometer on the head when it was running and the temp seemed fine. i guess if the thermometer is only a couple degrees off it makes a huge diff. well now i have basically a new motor. i know throwing parts at it is not the right way but since i did it all myself it prob cost me the same as bringing it to the shop for 85 hr. now i have spares. change those impellors often.

 

[stelladallas]

Re: followup rough running

Wait a minute. Are you saying that your problem was solved by changing out the water pump impeller? I have the same problem with a 70hp Johnson and have been going through the same thing that you have, for the last month. It still runs good a idle, but the minute I try to throttle up, it misses profusely. It has a good stream of water coming out the pee hole, but it seems my problem all started when I ran through some heavy milfoil and got the motor a little warm. Please answer me and be clear, because I am desperate and as you say, I had rather change out parts myself, before taking the thing to an $80 to $100 an hour qualified boat motor mechanic. Especially since I am try to live on Social Security and don't have that kind of money.

 

[parrilladk]

Re: followup rough running

I just posted similar problem with a 115 hp: I had one of my sons pump the bulb when giving the motor gas. It solved my problem. It must have been an air bubble in the gas line.

 

[stelladallas]

Re: followup rough running

I have tried and read so much, but I think I have tried that, but just to cover all my bases, I will try that again. I still have an in-line fuel filter and I think I will do away with that also. Does everyone think that Champion plugs are all that important? I have replaced my plugs with Autolite and I wonder if that may be the problem?

 

[nhdukes]

Re: followup rough running

stell dropping lower end and changing impeller and making sure all was clean and clear, which it seemed to be, but i poked and prodded anyway to make sure. worked for me. i was at the end of my rope because i was almost out of things to change. good luck

 

[nhdukes]

Re: followup rough running

didnt notice it was 2 mths since that last post. sorry. hope you figured it out.