kenmemphis
New member
"Greetings,
I have a 89 Mer
"Greetings,
I have a 89 Mercruiser 5.0 LX AlphaOne Thunderbolt IV that I have been working on. It was running pretty good but felt like it was idling a little rough. I decided to do a tune up and replaced the ignition coil, distributor cap and rotor wheel. I replaced the coil first and then test ran it for a little while. It seemed to run a little bit smoother. Next I replaced the rotor wheel and distributor cap. The sensor assembly was fairly rusty and there was also some small peices of material inside of the distributor that looked like the metal had been oxidizing a little bit. I used a still plastic brush to clean this up and then blasted it all out with air. While prying the rotor wheel off I noticed that the distributor assembly moved to the left a little bit. I figured it would be ok but that I would need to adjust the timing. Once I got it all back together it started and ran pretty good. I got out my timing gun and checked the timing. It was way over to the left of TDC around the very end of the measurement area, roughly 16 degrees. I turned the rotor and apparently turned it the wrong way because the timing mark moved even further to the left. At this point the engine ran rough and died. I moved the distributor back to where I thought I had started and it wouldnt start. I let it sit for a little while and then tried again with no luck. At this point I have tried to move it all around the area where I first started and have not been able to get it to start. I went ahead and ordered a new sensor assembly since it was pretty rusty. Once I replace that how can I get the distributor back to a position where it will fire correctly and start? I looked up my initial timing and it is supposed to be 8 degrees BTDC. FYI, my Thunderbolt IV must be one of the early ones because it does not have the purple/white wire to set the base ignition timing. I am very new to working on Mercruiser engines so please excuse my ignorance if I am saying any of this stuff wrong.
Thank You
Ken"
I have a 89 Mer
"Greetings,
I have a 89 Mercruiser 5.0 LX AlphaOne Thunderbolt IV that I have been working on. It was running pretty good but felt like it was idling a little rough. I decided to do a tune up and replaced the ignition coil, distributor cap and rotor wheel. I replaced the coil first and then test ran it for a little while. It seemed to run a little bit smoother. Next I replaced the rotor wheel and distributor cap. The sensor assembly was fairly rusty and there was also some small peices of material inside of the distributor that looked like the metal had been oxidizing a little bit. I used a still plastic brush to clean this up and then blasted it all out with air. While prying the rotor wheel off I noticed that the distributor assembly moved to the left a little bit. I figured it would be ok but that I would need to adjust the timing. Once I got it all back together it started and ran pretty good. I got out my timing gun and checked the timing. It was way over to the left of TDC around the very end of the measurement area, roughly 16 degrees. I turned the rotor and apparently turned it the wrong way because the timing mark moved even further to the left. At this point the engine ran rough and died. I moved the distributor back to where I thought I had started and it wouldnt start. I let it sit for a little while and then tried again with no luck. At this point I have tried to move it all around the area where I first started and have not been able to get it to start. I went ahead and ordered a new sensor assembly since it was pretty rusty. Once I replace that how can I get the distributor back to a position where it will fire correctly and start? I looked up my initial timing and it is supposed to be 8 degrees BTDC. FYI, my Thunderbolt IV must be one of the early ones because it does not have the purple/white wire to set the base ignition timing. I am very new to working on Mercruiser engines so please excuse my ignorance if I am saying any of this stuff wrong.
Thank You
Ken"