softbaitmaker Posted May 7, 2015 Report Share Posted May 7, 2015 Maybe some of you folks may have some ideas on this so will ask for help. Motor developed a miss on Sunday and it acted like spark plugs were misfiring so we put all new plugs in but it did not get rid of the miss. Brought her home and pull the cowling and ran a compression test. Each cylinder is holding 120-125 lbs. Thought it might be a coil because each cylinder has it's own coil to plug. Trouble is in number 4 cylinder. With boat running you can pull 1, 2, or 3 and motor drops out a lot. Pull number 4 and very little to no change. Moved # 1 coil to 4 and 4 to 1 and 1 was firing great but #4 still had same issue and did not drop out. That means it is not a coil issue. Checked all fuel filters for water and found none. Pumped out a quart of gas from tank into glass jar with primer bulb to see if any water in tank and got no water from tank. So now I am out of ideas. If anyone has experienced this issue and has any ideas on it all input would be greatly appreciated. When on the water it idles great but when you throttle up it starts to raise up and then falls on it's nose and won't throttle up if that helps. Quote Link to comment Share on other sites More sharing options...
trackertxw175 Posted May 7, 2015 Report Share Posted May 7, 2015 Fuel injected or carb? Quote Link to comment Share on other sites More sharing options...
softbaitmaker Posted May 7, 2015 Author Report Share Posted May 7, 2015 Fuel injected or carb? Carb's Quote Link to comment Share on other sites More sharing options...
SteveHTN Posted May 7, 2015 Report Share Posted May 7, 2015 Could possibly have trash in the fuel supply or the reed could be jamming. Quote Link to comment Share on other sites More sharing options...
trackertxw175 Posted May 7, 2015 Report Share Posted May 7, 2015 Since you have compression and spark, 1st thought was clogged injector. But since its carbs, would look at intake plenum for missing bolt or possibly gasket between it and head has cracked or at base of that carb. Quote Link to comment Share on other sites More sharing options...
country Posted May 7, 2015 Report Share Posted May 7, 2015 my suggestion is join Yamaha outboard parts forum, there is a ton of info for many engines and some very smart Yamaha mechanics, post your model,yr and horsepower and describe your problem most likely rodbolt will respond with answers, good luck and I hope you get it fixed soon Quote Link to comment Share on other sites More sharing options...
country Posted May 7, 2015 Report Share Posted May 7, 2015 I had a very similar issue with a Yamaha 115 2 stroke(carb) it was carb issues and a screen filter Quote Link to comment Share on other sites More sharing options...
softbaitmaker Posted May 7, 2015 Author Report Share Posted May 7, 2015 (edited) my suggestion is join Yamaha outboard parts forum, there is a ton of info for many engines and some very smart Yamaha mechanics, post your model,yr and horsepower and describe your problem most likely rodbolt will respond with answers, good luck and I hope you get it fixed soon Yep and my Son In Law is already conversing with several of the folks on that forum and they have began offering ideas. Thing is right now a lot of questions they are asking is Greek to him and I. We have a repair manual in the mail coming to me most any day now that covers everything from 1997 -2012 so maybe when the guys ask questions we can at least provide a somewhat descent reply back. One of the guys on that forum ask my Son In Law if it had a fuel pump under #4 cylinder and Tommy called me and ask me and i said I have no clue what a fuel pump even looks like on an outboard so we could not give him an intelligent reply. Edited May 7, 2015 by softbaitmaker Quote Link to comment Share on other sites More sharing options...
softbaitmaker Posted May 7, 2015 Author Report Share Posted May 7, 2015 I had a very similar issue with a Yamaha 115 2 stroke(carb) it was carb issues and a screen filter I'm thinking carb also but then it should not just be effecting 1 cylinder. It should be effecting at least 2 that work off that carburetor. If it will require any type of opening up the motor we will just have to bite the bullet and put it in the shop and wait the 3 weeks till they can get to it. We have checked every filter in the fuel system and they are clean and flowing great. Quote Link to comment Share on other sites More sharing options...
country Posted May 8, 2015 Report Share Posted May 8, 2015 in your boat pics it looks like a V4 130, the 115 is its little brother. under the cowl on left side of motor is a canister style filter, the fuel pump is right above it to the left. When I got my floats set right and removed that filter problem was gone and like yours it had one cylinder that seemed to not fire like it should, that fuel pump is located real close to the lower left cylinder, I am no Yamaha mechanic but after paying to have this done with terrible results I learned quite a lot about this V4 engine Quote Link to comment Share on other sites More sharing options...
Vafis Posted May 8, 2015 Report Share Posted May 8, 2015 Did you change your plug wires too? Quote Link to comment Share on other sites More sharing options...
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