Outboard Carb Problems

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  #1  
Old 06-27-03, 05:57 AM
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1998 Yamaha fourstroke -25 hp

I have a 1998 Yamaha fourstroke 25 hp outboard that has about 50 hours on it. It has been used very little in last year. I recently tried starting it (electric start) for a fishing trip. It started but when giving it gas it sputtered and spit and cut off. Upon restarting it it again ran on idle and slight gas but when giving more gas it sputtered again and quit. Thinking the carb was gunked up from sitting I ran a carb and choke cleaner thru the gas tank with a small amount of gas. Next day I tried it agin...was the same. I talked with yamaha repair shop and they said it was NOT the gas filter but was the carb needing cleaning. They wanted $150 to clean it. I thought this was a bit too much so I proceeded to try spraying carb cleaner thru small copper screw in side of carb as well as taking gas hose from fuel pump off and spraying carb cleaner thru these hoses back toward carb. I also checked the filter in the gas tank as well as getting new fresh gas.
After doing some things it seemed better but it still sputters when adding more gas. Idling seems good but not perfect. shakes and trembles even idling.
I see no easy way to take carb off nor do I see any carb adjusting screws to access jets.
I have cleaned my lawn mower carbs and have no real problem doing that. Consequentially I figured I can clean this carb on my outboard if I have a little technical help ..

Thanks for any help or suggestions..
 
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  #2  
Old 06-27-03, 07:34 AM
bryan77
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I have the same problem on my 95 28 hp johnson 2 stroke. it idles ok, some sputtering, but normally never stalls, an occasional cough if you will. then I have to punch it almost full throttle to go, If I go half throttle, it will start to accelerate, then bog down and stall completely. If I open it up it runs like a raped ape, but nothing in between....... so im interested in the answer to this question.
 
  #3  
Old 06-27-03, 08:28 AM
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Seems your problem is almost exactly like mine....I took my motor to the lake one day ...it started with difficulty...but after I did get it going it ran as you say...very fast but as i slowed to the launch ramp it started sputtering and would go for a second then cough..then go fast again then cough....almsot threw me out of the boat once as it caught and took off...It is dangerous like it is so I too am awaiting some sage advice from the " experts"...I know I can fix it if I could only figure out how to remove the carb ...hell..I can't even see any adjustment screws for the jets...Not happy with yamaha when they hide all the normal stuff you need to get to....
 
  #4  
Old 06-27-03, 01:28 PM
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Arrow Gummed Up Fuel Passages In Carb

Hello: Gents

All three engines have gummed up carbs from left over fuel going stale and gumming up the carb jets and fuel passages.

The carbs will have to be totally disassembled, cleaned out with professional strength carb cleaner in a carb cleaner tank. Might be possible to spray clean the fuel passages and jets, etc using canned automotive carb cleaner spray but not as positive a method.

Most likely I haven't covered all of the potential possibilities. Our resident service and repair professionals may offer additional suggestions, advice & help.

Check back on your question several times over the next few days for additional replies.
 
  #5  
Old 07-12-03, 07:27 AM
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Hello cough and sputter guys,
The yamaha carb is going to have to come off, there are very
small orofices that must be hand cleaned. it is very difficult
to remove and i would let the shop do it
Do you have an auxiliary filter installed in the boat? Get one.
A spin on style is best, yamaha makes a kit for about 40
dollars. It will help if you run the engine every two weeks
to reduce the amount to gumming, its also good for the
engines internal parts. Dont forget to hook up the garden
hose when you run it so you dont burn up the water pump.
The Johnson might free up the gum if you run some additive in
the tank, but its probably easier just to pull the carb off.
Not a big deal, easy access, and only the mounting gasket to
worry about. Pull it, drain it of gas, remove the bottom screws
and the lower jet. blow it out, put it on.

Sorry there wasnt better new Billsc6.
let me know if you want to try to remove it yourself
 
  #6  
Old 07-12-03, 09:54 AM
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Thanks but I am confused a little

I have oredered a shop manual for the four stroke Yamaha and am going to try and clean the carb myself. I am a little confused about your answer though. You say the Yamaha carb is difficult to clean and I should let a shop do it....then you say Johnson might do the trick with some additive...and that it is easy to clean. Do you mean the Johnson Motors????????????? I don't have a Johnson...I have a Yamaha ...You say take it off and remove the screws in the bottom and clean it and put it back on...Do you mean the Johnson Carbs are esy to clean or do you mean to take the carnb off my Yamaha and clean it..?
I realize that taking the carb off isn't going to be very easy but I have looked at it carfully and the only problem i see is what to do about the electrical connection...I hope it just comes out with the small screws and that it can be placed back as easy...I have cleaned auto carbs, boat carbs on Evinrudes, and lawn mower carbs so I am not exactly a novice when it comes to repairing things...Again..thanks for your help and I would appreciate your clarifying the comments about Johnson ...
 
  #7  
Old 07-14-03, 06:51 PM
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billsc6
I was addressing both your problem and bryan77's johnson
motor.
Sorry for the confusion.
 
  #8  
Old 07-15-03, 03:36 AM
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Thanks much for your help. After reading the post several times I sort of figured that you had spoke of both mine and the Johnson problem that was posted earlier.
I received the shop manual that i ordered and it has great blow ups withs instructions on removing and replacing the carb on 9.9 to 100 hp four stroke Yamaha engines.This is a great book and I am sure that I can clean my carb and get it running again with little problems. Wish I had known about it sooner because it will make repairs much easier. I ordered it from Amazon first but they were out and backordered with no real delivery date in sight. Then I found a smaller place in Fla who sent it priority mail so I got it in two days.
Again..thanks for the help.This is a great site for us do it yourselfers.
 
  #9  
Old 07-15-03, 05:25 AM
bryan77
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Sorry about the confusion, I should of put it on my own thread, but it appeared we had the same problems, didnt mean to confuse everyone.
 
  #10  
Old 07-15-03, 06:51 AM
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No Problem....us do it ourself guys need to keep a smile on our faces...cause the things we attempt to fix gives us enough grief..
 
  #11  
Old 07-25-03, 05:11 AM
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Success...

Okay guys...I took the carb off and disassembled it ...placed the parts in some stuff I got at AutoZone to soak it ...let it soak for about two hours...reassembled it and put it back on the motor...started it and it started immediately...it idled rough so I put two new spark plugs in and that corrected it....the old plugs were a mess..black and very oily...I checked the oil which had been recently changed and it was okay...
Anyway...it seems fine now...I was apprehensive about taking it off to clean it but after recieving the shop manual and looking at it close I had not one problem....I also recommend to anyone who plans on doing these small task at home that they get a small air compressor to blow out junk and fluids off the parts I have one that I have had about a year and it is the best investment I have made.
Again..thanks for the advice and help guys...Keep up the great work...
 
  #12  
Old 07-25-03, 02:06 PM
bryan77
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Thanks for the reply bill, I too have ordered a manual. last I heard its somewhere between here and florida......lol Hope to get it soon so I can rebuild mine. What was the name of the stuff you got at autozone, was it like a gallon jug, or a spraycan stuff? Glad to hear everything went ok.
 
  #13  
Old 07-25-03, 03:56 PM
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Bryan...

The stuff to soak it in is in a gallon paint type bucket...has a small basket inside to hold stuff so you can get it out easy...it is a combination of mineral spirits (paint thinner) and some alcohols...Works great..directions say to soak for tewnty minutes but I let it soak for two hours to be sure...it cost ten bucks but was well worth it...
did you order your manual from the place in Deltona Fla? I think the name was Motor world or something like that...I had mine shipped priority mail and it was here in two days...very good manual too...great details drawings and step by step directions...I had no trouble at all with my Yamaha carb...tested my motor today since it was nice for a change instead of rain....ran like a scared rabbitt...I am hooked on four stroke engines now...they cost a little more but they are well worth it...no more mixing oil and gas...and quiet..and runs forever on a gallon of gas...I saw one ...a ten horse Yamaha I think..they had it in a barrel of water and idling...said they put a gallon of gas in the tank 37 hours before and it was still going...
I spread a white towel on a table before taking my carb apart so I could see any small springs or jets that might fall out...It was very easy ...you can do it ...if you have a wrench or two with a couple screw drivers you should have no problems...
 
  #14  
Old 07-25-03, 07:18 PM
bryan77
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thanks for the good word, i hope to have the book in tommorows mail, if not maybe by monday. that gives me all week to work on it. I will give ya a reply back when I am done. have a good one
 
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