Yamaha 115 under a load will not exceed 1900rpm

[adamsrib]

Hello, i have a 2000 yamaha 115 saltwater sieris outboard, last week fishing i was trolling at 2000 rpm most of the day, on the way home i was unable to run the boat past 1900 rpm all the way home took several hours to get in. i can put it in nuetral and rev it up to 5000 in the water out of the water i can put it in gear and rev 5000 as well. it looks like there is a carbon type oil leak a few drops comming from my exsaust by the prop but it stopped leaking. and my lower unit oil is fine. any ideas i cant bring it to the shop for three weeks they are all backed up and i want to go fishing..<br /><br /><br />thanks all.

 

[Backlash]

Re: Yamaha 115 under a load will not exceed 1900rpm

Hey Rib, You'd better check the plugs & run a compression check on the Yammy. Could be all that low speed trolling choked it up with carbon. Try decarboning with SeaFoam & change the plugs afterward.<br />Backlash

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

backlash<br />sounds good i am going to try it this weekend, that makes perfect sence i hope it does the trick. have you seen this before in other engines?

 

[finnaddict98]

Re: Yamaha 115 under a load will not exceed 1900rpm

A real quick check...if you motor has an input to attach the carb cleaner (looks like the fitting for a bike tire)..there might be a red plastic turn switch right behing this adapter.. On OMCs the red "THING" pointing down is normal operation. At the 3 oclock position is it in full choke..(like pushing in the key)this COULD cause the oily run off out of the hub. What you are seeing is the excess premix that cant be burnt off, running out with the exhaust. I accidently knocked the switch with the engine cowling and thought I burnt up a lower unit seals....it was just that the switch had been bumped into a full choke position..incidently straight up is OFF on my motor. The **** thing would not run until I discovered the position was incorrect. Id have to put it in nutral and gas the heck out of it to get it to even start..then it smoked like crazy..and ran rough as hell. It would not idle either.....I know its not an OMC you have, but maybe you have a similiar "switch" that got knocked out of position..I know mine caused me alot of headache until it was discovered...<br /><br />Let me know what the culprit was...<br />good luck

 

[JB]

Re: Yamaha 115 under a load will not exceed 1900rpm

Howdy Adamsrib. I suspect that you are down a cylinder or two.<br /><br />Remove plug wires, one at a time, while engine is running. If no noticable change, a dead cylinder. Drop in rpm, a cylinder making power.<br /><br />If the plug wire from a dead cylinder can make a 1/2" arc to the block, ignition is okay and the problem is fuel or compression related.<br /><br />Fuel problem? I don't know about Yammys. Good luck.<br /><br />Red sky at night. . . <br />JB

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

hi guys ive done the spark plug test and found that two of my cylinders are dead both on the same side of the engine. i am getting spark to all 4 wires and all of my cylinders have the same compretion of 130 the book says it should be 105.6 for all. the dead cylinders have a raw gas smell and you can tell that they were not fireing on the way in. any ideas? it looks like i will be out of the water untill the 18th when i can take it to the shop.<br /><br />thanks again rib.

 

[my new fishmaster]

Re: Yamaha 115 under a load will not exceed 1900rpm

Rev up to 5000! With your ear muffs on you should never go past 2000 or so. I will bet your impeller is muffed.

 

[TONY H]

Re: Yamaha 115 under a load will not exceed 1900rpm

Good compression, getting gas to all cylinders and good spark to all 4 wires...I say you have two fouled plugs. Run some sand paper through them and try again. Better yet, throw in a set of old 'good ones'and see how you do. I have had terrible luck with NGK spark plugs on both the boat and the motorcycle. NGK has gotten an earful from me last year on their decreasing quality. <br />Hopefully it is a cheap fix like this.

 

[Backlash]

Re: Yamaha 115 under a load will not exceed 1900rpm

Hey Rib,<br />If you're getting strong spark through all four plug wires, yet two cylinders aren't firing....it's got to be faulty spark plugs in those two cylinders. What do the plugs look like? My original thought was possible carbon buildup....I always like to go with the easiest things first . Let us know how the plugs look.<br />Backlash

 

[Backlash]

Re: Yamaha 115 under a load will not exceed 1900rpm

Hey Tony,<br />You must type faster than I do! <br />Backlash

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

the two plugs that fire are very carbed up but the ones that dont fire dont look to bad i will change them when i get home and see what it does. do you think both cylinders would go bad at the same time due bad plugs? i hope thats what it is i am iching to fish.<br /><br />thanks again.<br />rib

 

[Backlash]

Re: Yamaha 115 under a load will not exceed 1900rpm

Hey Rib,<br />I'm basing my theory on the fact that you're getting good spark TO the plugs. If the plugs aren't firing, they won't get carboned up like the ones that are. Try switching the plugs & see if the miss moves with the plugs. Keep us posted.<br />Backlash

 

[JB]

Re: Yamaha 115 under a load will not exceed 1900rpm

Howdy, Rib. Don't forget that too much fuel will prevent firing, too. If the same carb feeds those 2 cylinders, check for a stuck float causing flooding.<br /><br />Red sky at night. . .<br />JB

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

Ok guys i am cutting out of work early to go try some of this stuff out good idea about swithcing the plugs to see if the problem moves with it i am also going to decarb and check the carbs that makes good sence if on carb supports that side. i really apreciate the help i will keep you informed. <br /><br />rib

 

[NJBOATS]

Re: Yamaha 115 under a load will not exceed 1900rpm

check the fuel pump diaphram if the plugs that are gas fouled are opposit the pump. remove the pump and see if fuel runs out of the hole . easy enough to do hope this helps out catch em up!

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

J.B and Backlash and everyone else i thank all of you for your help, i switched the plugs to the other side and the problemb moved with the plugs i changed the plugs ran it and it workes perfect so i went fishing saturday and caught 15 dolphin with my friends i tried to attach an image but am not sure how.<br /><br />thanks again

 

[JB]

Re: Yamaha 115 under a load will not exceed 1900rpm

Excellent, Adamsrib! Congratulations.<br /><br />I sure wish I could have been with you and your friends. The only thing I like as well as dolphin (dorado, mahimahi, etc.) on light tackle is dolphin filets on the grill with a bottle of Blue Nun.<br /><br />Red sky at night. . .<br />JB

 

[mikeyb]

Re: Yamaha 115 under a load will not exceed 1900rpm

Hey Guys,<br /><br />Sorry for dredging up an old topic but it is of interest to me.<br /><br />AdamsRib, if you are still about, did you just change the plugs on the Yammy for new ones or did you change make?? ie recommended NGK's or something else??<br /><br />I have two Yam 115's and twin Yam 75's and have had plug problems over the past year in the 115's.<br /><br />Any info much appreciated.<br /><br />Mike.

 

[adamsrib]

Re: Yamaha 115 under a load will not exceed 1900rpm

no i just changed plugs i have been running NGK since i got the engine i now carry several extras with me incase it happens again i am usually out very far and cant risk loosing my only power supply. i may go to champion plugs if it happens again.