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2003 Yamaha 70 tune up question Model TLRB

M

Mac300

Member
I have a Clymer manual for the above motor. The manual covers many years and is generally accurate but not always dead on for my year. Does anyone have a manual for this model? Specifically I am looking at the sync and link part of the throttle/carb adjustments. The info in my manual is not correct for my motor. It says to adjust the linkage to a length actually longer than the rod. I found one for another year model that was different so I’m hoping to find the specific one for my engine. I’m attaching the page from my manual for reference. My issue is that it runs great at idle and 1/3rd to full power but rough at “trolling” speed. Wanting to go thru the process to make sure timing and settings are all correct. Thanks!
 

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A lot of things do not go out of adjustment on modern motors.-----Electronuc ignition and fixed jet carburetors just work well.-----What is this motor doing / not doing that leads you to make adjustments?
 
It had become very hard to start the first time every day. After that, fired right up. It also runs rough if you gave it just enough fuel for “trolling” speed…just above a no wake speed. Runs great at idle and at faster speeds…like a sewing machine. This motor doesn’t have a choke…it has the fuel enrichment system that has a small diaphragm pump and needle plunger on 2nd carb to give extra fuel when the engine is cold. I rebuilt/cleaned all three carbs and the enrichment primer pump and it fires right up now. I also had 1 bad spark plug lead and replace it. All coils are within the resistance specs. At full throttle the carb plates aren’t anywhere near wide open but it runs fast enough for me (31mph). If I adjust it to be fully open the motor runs extremely high at idle. I just wanted to start from scratch and make sure all linkages and adjustments were correct. When I bought this boat it would run fast (44mph). The prior owner had it adjusted where the throttle plates were fully open and then had a spring rigged up to physically pull the throttle lever linkage back to slow idle. I felt it was exceeding WOT rpm’s and I wasn’t at all comfortable with his set up and made adjustments. I attached a tach to a spark plug lead and if it’s accurate I’m hitting approx 4600 at WOT…my manual says 5-6000. I will check the timing next weekend…left my light at home. But would it run this smooth at idle and faster speeds if timing was off? It’s just that “bumped up” increase in speed where it’s rough. Specifically…when we are jug fishing and picking up jugs and I go from idle to move 30 yards to get to the next jug…hoping it’s just a small adjustment I need to make. Thanks!
 
Thank you. I found that exact diagram online and the poster said it was from a 1999 manual IIRC. I was able to adjust to the lengths indicated. The length from my manual is longer than the actual rod. I have yet to check the timing. Will do that next and go thru the procedure outlined in the manual. Thank you
 
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