bjcsc
Lieutenant Commander
- Joined
- Jun 1, 2006
- Messages
- 1,805
Recently I posted this thread about troubleshooting a sudden no spark on all cylinders that happened to my friends motor after being shut down normally on the water. After we solved that problem, we decided to check the timing as we replaced enough ignition components to warrant it in our opinions. I decided to start a new thread so it could be searched easier as we learned a lot getting this done.
With the Joe Reeves procedure in hand we started out. I pieced together the procedure from various posts here as there does not seem to be one that contains all the different tips on how to do it, or explain how to do some of the things Joe says must be done. For example, this motor has the fast start feature which he says must be disabled but he doesn't say how to disable it. This feature gets to the powerpack via the yellow/red wire in the port side connector. We bypassed it by rigging a momentary pushbutton switch up as a remote starter and disconnecting the yellow/red wire at the solenoid (it goes to the powerpack from there) and then taking the connector for the overheat sensor (in between the port cylinders) and grounding the white/blk wire (reported to be black/wht in a different post here but is definitely wht/blk). We were seeing about 20? BTDC at WOT using Joe's method. We tried to adjust to 16? and it simply wasn't there. We could get it to ~18? but that was it. While we were doing this and watching the linkage and learning what all the parts do, we noticed the timer base seemed to be dragging a bit and not going all the way to the stop at idle. We decided to take a different approach and hooked the yellow/red back up to the solenoid and reconnected the temp sensor leaving the engine with everything electrical connected as normal.
We started by removing the timing wheel and the new optical sensor we just put in and cleaning the timer base and the top of the flywheel cover where it mates with paint thinner (it's plastic so no lacquer thinner/acetone/mek, etc.). The last 18 years worth of grime, which was a thin film you could barely see, came out off and out of the grooves and once reinstalled it moved like it was on bearings. I'm not a marine mechanic, but I have a thorough understanding of how timing works on engines. After studying the linkage and deciding what the adjustments on everything were designed to do, we were ready. As a note, the factory manual was actually pretty confusing on how to make some of the adjustments (to us non-boat techs anyway) and studying the linkage is what made it all make sense.
The first thing we adjusted was the roller arm, "A"...
Quite simply the circled screw is loosened and this is adjusted so that when at idle, the roller on the end just makes contact with the spark cam plate, "B" without moving it at all from contact at point "C" and then the screw is tightened back up. When you advance the throttle, "B" should begin to move immediately and together with the plates on the carbs.
Next we decided to abandon the Reeves timing procedure and opted for our own that incorporates some of what Joe described but made more sense to us. First, we disconnected the throttle linkage from the timing parts by removing the two screws "D" and sliding the plastic linkage retainer which is under the plate that is under the screws in the direction of the arrow. This allowed us to pull up on the roller arm, sliding it up and off of the shaft coming from the carb plate linkage. With the carb linkage detached, we put the end of the roller arm back in, slid the retainer back in and replaced the screws. As a safety precaution, we wired the carb plate linkage so the plates could not open.
Now we're ready to run it. We hooked it up to muffs and started it up. We let it idle until it warmed up (about 10 minutes). This takes care of any cold engine fast start electronic advance, thus not requiring that system to be disabled. Also, the engine is running so there's no need to set it 4? less than the 20? our engine calls for at WOT. We turned off the engine. Now we're ready to adjust the idle timing and the WOT timing. To adjust the timing, we loosened the screw circled in red and left it loose until both idle and WOT were adjusted. We restarted the engine and let it run while we hooked up the timing light to the #1 cylinder (starboard side top). Next we checked the timing at idle and got 3? ATDC. Not bad and in spec, but we adjusted it to 4? ATDC as called for in the manual. To adjust it, we moved the tab marked "F" toward the timing wheel and slid it in the notches toward the "-", verifying that the cam plate "B" still had contact at point "C". The top of the notched center piece is marked + and - if you look at it closely. Next we were ready for WOT timing. Remember, we disconnected the throttle linkage and wired the plate linkage shut. With a finger at point "G" on the throttle lever, we pushed the linkage slowly in the direction shown by the arrow until the part of the lever marked by the star was hard against the stop marked "H". As we did this, the roller on the end of the roller arm "A" moved the cam plate "B" toward and to full advance and the RPMs steadily increased to about 2400 or so. We were now at WOT timing, but because the throttle plates were wired closed, we were not at WOT (6000RPM). With the throttle lever still hard against the stop. we shot the timing and got 21? BTDC. In spec, but we adjusted it down to 20? as called for. To adjust it, we pulled out on "E" and moved it two notches toward "-". We tightened up the screw circled in red and rechecked. Everything was spot on.
Satisfied with the timing, we shut the engine down, unwired and reattached the carb plate linkage and buttoned her up.
I hope this makes this procedure clearer for future users...
With the Joe Reeves procedure in hand we started out. I pieced together the procedure from various posts here as there does not seem to be one that contains all the different tips on how to do it, or explain how to do some of the things Joe says must be done. For example, this motor has the fast start feature which he says must be disabled but he doesn't say how to disable it. This feature gets to the powerpack via the yellow/red wire in the port side connector. We bypassed it by rigging a momentary pushbutton switch up as a remote starter and disconnecting the yellow/red wire at the solenoid (it goes to the powerpack from there) and then taking the connector for the overheat sensor (in between the port cylinders) and grounding the white/blk wire (reported to be black/wht in a different post here but is definitely wht/blk). We were seeing about 20? BTDC at WOT using Joe's method. We tried to adjust to 16? and it simply wasn't there. We could get it to ~18? but that was it. While we were doing this and watching the linkage and learning what all the parts do, we noticed the timer base seemed to be dragging a bit and not going all the way to the stop at idle. We decided to take a different approach and hooked the yellow/red back up to the solenoid and reconnected the temp sensor leaving the engine with everything electrical connected as normal.
We started by removing the timing wheel and the new optical sensor we just put in and cleaning the timer base and the top of the flywheel cover where it mates with paint thinner (it's plastic so no lacquer thinner/acetone/mek, etc.). The last 18 years worth of grime, which was a thin film you could barely see, came out off and out of the grooves and once reinstalled it moved like it was on bearings. I'm not a marine mechanic, but I have a thorough understanding of how timing works on engines. After studying the linkage and deciding what the adjustments on everything were designed to do, we were ready. As a note, the factory manual was actually pretty confusing on how to make some of the adjustments (to us non-boat techs anyway) and studying the linkage is what made it all make sense.
The first thing we adjusted was the roller arm, "A"...
Quite simply the circled screw is loosened and this is adjusted so that when at idle, the roller on the end just makes contact with the spark cam plate, "B" without moving it at all from contact at point "C" and then the screw is tightened back up. When you advance the throttle, "B" should begin to move immediately and together with the plates on the carbs.
Next we decided to abandon the Reeves timing procedure and opted for our own that incorporates some of what Joe described but made more sense to us. First, we disconnected the throttle linkage from the timing parts by removing the two screws "D" and sliding the plastic linkage retainer which is under the plate that is under the screws in the direction of the arrow. This allowed us to pull up on the roller arm, sliding it up and off of the shaft coming from the carb plate linkage. With the carb linkage detached, we put the end of the roller arm back in, slid the retainer back in and replaced the screws. As a safety precaution, we wired the carb plate linkage so the plates could not open.
Now we're ready to run it. We hooked it up to muffs and started it up. We let it idle until it warmed up (about 10 minutes). This takes care of any cold engine fast start electronic advance, thus not requiring that system to be disabled. Also, the engine is running so there's no need to set it 4? less than the 20? our engine calls for at WOT. We turned off the engine. Now we're ready to adjust the idle timing and the WOT timing. To adjust the timing, we loosened the screw circled in red and left it loose until both idle and WOT were adjusted. We restarted the engine and let it run while we hooked up the timing light to the #1 cylinder (starboard side top). Next we checked the timing at idle and got 3? ATDC. Not bad and in spec, but we adjusted it to 4? ATDC as called for in the manual. To adjust it, we moved the tab marked "F" toward the timing wheel and slid it in the notches toward the "-", verifying that the cam plate "B" still had contact at point "C". The top of the notched center piece is marked + and - if you look at it closely. Next we were ready for WOT timing. Remember, we disconnected the throttle linkage and wired the plate linkage shut. With a finger at point "G" on the throttle lever, we pushed the linkage slowly in the direction shown by the arrow until the part of the lever marked by the star was hard against the stop marked "H". As we did this, the roller on the end of the roller arm "A" moved the cam plate "B" toward and to full advance and the RPMs steadily increased to about 2400 or so. We were now at WOT timing, but because the throttle plates were wired closed, we were not at WOT (6000RPM). With the throttle lever still hard against the stop. we shot the timing and got 21? BTDC. In spec, but we adjusted it down to 20? as called for. To adjust it, we pulled out on "E" and moved it two notches toward "-". We tightened up the screw circled in red and rechecked. Everything was spot on.
Satisfied with the timing, we shut the engine down, unwired and reattached the carb plate linkage and buttoned her up.
I hope this makes this procedure clearer for future users...
