Mark42
Fleet Admiral
- Joined
- Oct 8, 2003
- Messages
- 9,334
Been having some problems with a 2003 90 hp johnson w/rebuilt powerhead. Motor has a new VRO. New fuel canister,
Situation is this:
- Motor now starts and runs fine for 1 hour, then starts to break up, and in about a minute or two, will just run roughly at low idle.
- The following day, it will start and run great for about 1 hour, then breaks up same as before.
- I noticed that the volt gauge sometimes registers just 12 volts, then a minute or two later jumps to 14 or 15 volts, depending on the engine RPM.
- Engine is pumping water well, and registers 15 psi on the water pressure gauge.
- The System Check lights in the tach light up sequentially when ignition is turned on. They do not light up when the engine is running bad.
- Today I ran the boat for an hour and while at near WOT turning 4200 rpm, it "mis-fired" for a beat, then about 10 seconds later, it did it again, and ten 2 seconds later, again, and I backed off the throttle and headed right for the dock. Once the RPM dropped below about 2500 rpm, it will only run at just off idle, and very rough. Once tied up at the dock, I pump the primer bulb, but it made not difference. Then I disconnected the spark plugs one at a time to see if all were firing, and it appears that the port side top cylinder, and starboard side bottom cylinder made no difference when disconnected. But it was hard to tell because it was runny pretty crappy anyway.
So, I am thinking this is an ignition issue. Just not sure which component could be the culprit: Stator, Regulator, or Power Pack.
What do you think? Any suggestions are appreciated.
Thanks!
Mark
Situation is this:
- Motor now starts and runs fine for 1 hour, then starts to break up, and in about a minute or two, will just run roughly at low idle.
- The following day, it will start and run great for about 1 hour, then breaks up same as before.
- I noticed that the volt gauge sometimes registers just 12 volts, then a minute or two later jumps to 14 or 15 volts, depending on the engine RPM.
- Engine is pumping water well, and registers 15 psi on the water pressure gauge.
- The System Check lights in the tach light up sequentially when ignition is turned on. They do not light up when the engine is running bad.
- Today I ran the boat for an hour and while at near WOT turning 4200 rpm, it "mis-fired" for a beat, then about 10 seconds later, it did it again, and ten 2 seconds later, again, and I backed off the throttle and headed right for the dock. Once the RPM dropped below about 2500 rpm, it will only run at just off idle, and very rough. Once tied up at the dock, I pump the primer bulb, but it made not difference. Then I disconnected the spark plugs one at a time to see if all were firing, and it appears that the port side top cylinder, and starboard side bottom cylinder made no difference when disconnected. But it was hard to tell because it was runny pretty crappy anyway.
So, I am thinking this is an ignition issue. Just not sure which component could be the culprit: Stator, Regulator, or Power Pack.
What do you think? Any suggestions are appreciated.
Thanks!
Mark