"I sent this to Joe Reeves, I
"I sent this to Joe Reeves, I thought y'all would like to view our conversation.
Hi Joe... We have chatted before....
I was wondering if you would give me some advice... The subject of the discussion is a 1999 70 HP evinrude... It runs on 3 cylinders for a while then the lower cylinder (I will refer to it as Cyl 3) drops out. I have replaced the coils, Power pack and now I guess I am going to replace the trigger sensor. I tried to perform the electrical check that was listed in my repair manual but it was not very deterministic... Since it runs fine for a short time before acting up I am assuming it is heat related and not a shorted sensor wire. When failure happens I have no spark at the plug.
So here is what I would like your comments on...
Should I just bag any further diagnostics and replace the stator assembly
Can I simply buy a sensor for replacement on Cylinder 3? The Stator assy is a $180 after market part...
Joe's response
Larry,
Before throwing any more parts at that engine....... when that #3 cylinder stops functioning, I would carefully remove the spark plug boot (using insulated pliers) from that plug to see if it is actually still firing or not. It's possible that a fuel problem could exist.
Many years back, I encountered a problem such as yours that really drove me and a few other mechanics up the wall. Finally I went out in the boat with the owner..... a bass boat with a V6 that did close to 80 mph.... something that I really did not enjoy. Eventually the engine dropped a cylinder BUT still had ignition (spark). Removing the carburetor that effected that cylinder and dismantling it revealed a small almost transparent bug that would float on top of the fuel but after some time would get drawn down into and would clog the high speed jet. A freak happening that only happened to me once..... but I never forgot it.
The timing sensor? Could be, but I think that the sensors on that engine are sealed into the timer base, meaning that you would be required to buy the complete timer base assembly.
Bottom line..... Check the spark as mentioned above before going any further with parts purchases.
Joe Reeves"
"I sent this to Joe Reeves, I thought y'all would like to view our conversation.
Hi Joe... We have chatted before....
I was wondering if you would give me some advice... The subject of the discussion is a 1999 70 HP evinrude... It runs on 3 cylinders for a while then the lower cylinder (I will refer to it as Cyl 3) drops out. I have replaced the coils, Power pack and now I guess I am going to replace the trigger sensor. I tried to perform the electrical check that was listed in my repair manual but it was not very deterministic... Since it runs fine for a short time before acting up I am assuming it is heat related and not a shorted sensor wire. When failure happens I have no spark at the plug.
So here is what I would like your comments on...
Should I just bag any further diagnostics and replace the stator assembly
Can I simply buy a sensor for replacement on Cylinder 3? The Stator assy is a $180 after market part...
Joe's response
Larry,
Before throwing any more parts at that engine....... when that #3 cylinder stops functioning, I would carefully remove the spark plug boot (using insulated pliers) from that plug to see if it is actually still firing or not. It's possible that a fuel problem could exist.
Many years back, I encountered a problem such as yours that really drove me and a few other mechanics up the wall. Finally I went out in the boat with the owner..... a bass boat with a V6 that did close to 80 mph.... something that I really did not enjoy. Eventually the engine dropped a cylinder BUT still had ignition (spark). Removing the carburetor that effected that cylinder and dismantling it revealed a small almost transparent bug that would float on top of the fuel but after some time would get drawn down into and would clog the high speed jet. A freak happening that only happened to me once..... but I never forgot it.
The timing sensor? Could be, but I think that the sensors on that engine are sealed into the timer base, meaning that you would be required to buy the complete timer base assembly.
Bottom line..... Check the spark as mentioned above before going any further with parts purchases.
Joe Reeves"