johnson 15 won't ramp up

My seahorse starts and runs After the 1st time you go to high speed and then go back to a slow speed it won't go back to fast. if i give it gas it dies, will run ok at slow but wont go to fast-just dies. it's not hot and it spits water
getting gas any suggestions/comments.

Re: johnson 15 won't ramp up

Welcome to iboats. It would help if we could know the model/year of your motor.

Re: johnson 15 won't ramp up

it is a J15RCNC
I believe that makes it a 1982
SN. E5616273

Re: johnson 15 won't ramp up

You say it spits water. Is it a steady/constant stream or like you said, spitting? Best of luck. Rick.

Re: johnson 15 won't ramp up

When you try to speed it up after sl;owing down, does the twist grip move easily or does it have a hitch? With those older style throttle rod gear linkage, you may have a tooth broke or the mesh between the 2 gears sloppy. Or your timing plate is gunked up & dragging. Even a wiring from under the timing plate may be interfearing with the timing plate from moving.

Possibly a partially plugged main jet.

Re: johnson 15 won't ramp up

a nice staedy stream of water coming out. the throttle seems "loose" with play in it. my son and i looked at it and when you twist the handle the shaft moves some before it starts to move the gears. also when your motoring along it seems to "gain" speed even though you aren't moving the handle. i know that there is slop in this assembly -but my problem is that i had the boat out and motorted over a mile at a medium speed, then shut it off, fished awile, started the motor went another mile at say 3/4 speed , again stopped and fished, then just for fun gave it the full throttle and raced up and down for 5-7 minutes and then had to throttle back for the no wake zone , then it killed, it starts right back up every time but if you try to ramp it up -it dies, will go a troll speed but not faster! please explain about the throttle plate?
this is a great forum!!! i just love that so many people are willing to help a guy who basically is just a aluminum boat fisherman! I had grandpa's 9.9 and like a fool traded it with my old boat for this newboat with this 15- upgraded? remains to be seen