Got a rather weird scenario that sounds similiar to others. However, mine is a bit unique which I feel must be posted. I have an 89 Black Max 135. Most of the time it runs fine. However, out of the blue, when idleing, it sounds as if it starts loosing spark(what it feels like) and running rough. When you try to speed up it shakes and then stalls. After, it will fire several times and then after several more attempts it won't even start. If it sits for a while it will fire back up and run great. At times the problem never occurs no matter how hard I run it. This is the second time this has happened in the past 3 weeks and I need some advice on what could cause this erratic behavior. Please Help!
<br /><br />Your fuel pump may be at fault. That year used check valves that pucker and lose efficiency to where they won't pump fuel at idle. Rebuild kits are cheap and the job is fairly easy. But you have to be careful driving the plastic rivets that hold the checks in place.<br /><br />The originals (like yours) were a thin rubbery material that pucker badly with fuel additives. They changed them and made them thicker, but puckering was not eliminated. Now they use mylar discs that were originally used as a backing for the rubber ones. They seem to work a lot better and are much more tolerant of gasolines these days.