1984 90hp VRO4 Run Problem

My 1984 Johnson 90hp VRO4. I have rebuilt carbs. Replaced fuel pump. Have cleaned out fuel tank. Sometiumes it will get where it will start to die out whem you are throttled up an sometimes it will not idle properly. If you pump up the primer bulb it will start to run properly. Yesterday I used about a half of tank of fuel. Then toped off fuel tank, It ran about 1/4 of tis tank full and started to act up.I pumped up on primer bulb and it started to run OK, until was going to load back on trailer and then it didn't want to Idle properly. The engines compression is 110lbs on all four cylinders.

Re: 1984 90hp VRO4 Run Problem

I'd start by checking all connections in the fuel system for tightness. An air leak can cause problems.<br /><br />The other thing you might want to check is spark on all the cylinders. The spark should be able to jump about 1/2 inch and be bright blue. If you don't have a sparck checker, you can get one at any auto parts place for about $5.<br /><br />While it is acting up, try pulling/replacing the plug wires one by one (use insulated pliers). If it runs worse after pulling the wire, then you know that that cylinder was working. If there is no change, then that cylinder wasn't firing. Can at least narrow you search to the fuel and/or spark for that cylinder.<br /><br />Good Luck!

Re: 1984 90hp VRO4 Run Problem

Oh Yeah...I forgot....Welcome to the forum!<br /><br />Brew