I?m working on a Mariner 50 hp, 4 cylinder, 2 stroke, electric start, serial # 65428531. Below is a photo of my flywheel. Room the number left that zero ?degrees BTDC? and also the numbers best of zero ?degrees ATDC??
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2. The Mercury shop manual says to change timing in forward equipment with engine running and to use a test tank or launch the boat. Is this for cooling or does the prop need submersion in water because that resistance while working in forward gear? If only for cooling, have the right to I finish timing adjustments on soil while cooling through a muff (prop eliminated for safety)?3. Adjusting the ?maximum spark advance? requires progressing the throttle in forward equipment until the point out on the flywheel check out 32 levels BTDC. Just how much force will the prop be generating in ~ this point? can this be done while bound up at the dock, or will I should be cost-free since the engine will be under power in front gear? OR, room the RPMs low sufficient when the 32 degree BTDC mark is reached that ns won?t need to worry around how much thrust the engine is producing? Again, curious to understand if this component of the adjustment can be done with a cooling muff if the watercraft is on the trailer.Thanks in advancement to all the great people who assist me the end with understanding this.

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ticondo46Seaman Apprentice
JoinedJan 30, 2012Messages31
Re: Timing: just how do I read my flywheel, and other timing questions?At idle, certainly do it through the propeller in the water. With just the muffs on, friend don"t have actually the same ago pressure on the exhaust, and also it would give you a not correct reading.Don"t effort a WOT adjustment of preferably spark advancement with the watercraft in the water however! at the very least, you are going to obtain covered in splash, and at worst, you will be climbing over the dock! I"m not an especially familiar with your exact form of motor, but I would say that if nobody disturbed the original factory settings, you have to be OK because that maximum spark advancement once you"ve obtained the idle spark advancement right. Alternatively, you deserve to do a max spark advancement adjustment with the lower unit in the water, yet the prop bring away off. Simply blip the gas towards WOT, have actually somebody hold the timing irradiate to the marks and check it out. Don"t store the motor at high RPM"s and also no load for anything an ext than a second or so!Good luck.
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Chris1956Supreme Mariner
JoinedMar 25, 2004Messages24,774
Re: Timing: just how do I review my flywheel, and also other time questions?Fish, The time marks left of zero is BTDC. Eliminate all spark plugs other than #1 and also install these into their plug wires and ground them to the block. Currently you have the right to crank the engine to set the timing, and also it will certainly not start. Friend may set idle and also max spark advancement in this method in her driveway. Carb mixture adjustment requirements to be done in the water, engine warm and in forward.32* max advance is a lot. Due to the fact that I carry out not understand the year of that motor, it may or might not be right, or still recommended.
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Re: Timing: exactly how do I check out my flywheel, and also other timing questions?Thanks! That?s a great bit of information to assist me out. I simply scanned the 3 pages the end of my shop manual which describe timing adjustments and specifications, in instance they will aid any of friend folks who are gracious enough to aid me recognize the material.
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1. For my engine?s serial number, the ?primary pickup? timing should be collection between 2* BTDC and 2*ATDC. Is this what I desire to aim for when adjusting the time at idle speed? 2. Max Spark advancement should be set to 30* BTDC, but should be readjusted at 32* BTDC in order to acquire 30* follow to the manual. Additionally, the chart specifies 33* BTDC when cranking v starter. I gather the if i do adjust Max Spark advancement in my driveway by cranking with the starter motor and also plugs pulled and grounded, I want the flywheel reminder to read 33* BTDC. Carry out I understand the chart numbers top top pg 1 correctly? 3. The time light has actually a small dial on the ago of it because that spark advance. I mean I need to leave this in ~ 0*? Would setup this dial ~ above the timing irradiate at 3* then average that i would change Max Spark development so the pointer showed 30* top top the flywheel? Sorry for being such a layman, but you folks room the best teachers!4. I?ve to be doing a whole bunch of work to this engine and also figured a timing adjustment would be a good measure come ensure that every little thing is set correctly. Ns dismantled the throttle bar to lubricate it"s friction points, but did no touch any of the avoid screws, so theoretically the prevent screws have to still it is in on target, and also these space what actually collection the timing in between the trigger assembly and the mechanical components of the throttle lever, correct?Thanks again for all your help! ns can"t give thanks to you enough.
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Chris1956Supreme Mariner
JoinedMar 25, 2004Messages24,774
Re: Timing: just how do I read my flywheel, and other time questions?With every spark plugs the end (remove prop), other than for #1, advance the throttle till the carb is just ready to open. Put timing light with zro advancement set, crank motor and read timing. The should complement primary pickup spec. Change as specified.Advance throttle completely and inspect that carbs are all the way open. Crank motor and read max advance. I would usage 30* BTDC together the spec, because I execute not know why the time would change if the motor was running.There should be set screws because that minimum idle (Idle stop), max spark advance and max throttle. The actuator plate must rotate because that adjusting main pickup timing.
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Re: Timing: how do I read my flywheel, and other time questions?Thank girlfriend Chris.I"m not sure why that would speak to for 33* BTDC when cranked by starter motor but call because that 32* BTDC v engine running. Ns don"t know the real guts of an engine well enough to understand why that would certainly be stated by the Mercury organization manual. I"m likewise in the dark top top why 32* BTDC should be provided to achieve 30* BTDC. I think it"s time for a brand-new thread on that topic, and also maybe someone will have the ability to say why the digital timing features of this ignition mechanism require setup max advancement at 32* BTDC to obtain 30* BTDC.
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aussieflashLieutenant junior Grade
JoinedFeb 5, 2011Messages1,004
Re: Timing: exactly how do I read my flywheel, and also other timing questions?Your engine is a 1984 model.Spark advance characteristics is the same as my V6 1988.I didnt shot to recognize it....I just did together I to be told...lol.All mine timing was done in ~ cranking only...much easier.I couldnt imagine make the efforts to adjust max while engine in water???Is that even possible.

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Chris1956Supreme Mariner
JoinedMar 25, 2004Messages24,774
Re: Timing: exactly how do I review my flywheel, and also other time questions?Aussie, i think his engine is much older 보다 1984. Ns think the is late 60s or beforehand 70s.