Trying to sync a 1987 Classic 50 need a little help?

huntxtrm

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Ok, I have 1987 Classic 50. From all the info I can find. My linkage adjustments look like this? Linkage.jpg I am going to go by this write up I found on this Forum! Awesome! Questions are. 34 degrees? Or, 21? I don't know what "Direct Charge" means, or how to tell this one is or not? It is a 1987 Classic 50. I am having a really hard time finding a manual for it. Or, at least one that I can be confident covers it. Don't want to buy a manual, just to find out, my motor is not in there. Things I cant seem to locate. "Main Throttle Stop", 1st Throttle pickup, i think is adjusted by the 2 screws bottom of the actuator plate? I do not know where the "Idle Stop Screw" is either. I know some of iti is in my pic, but probably not labeled as the directions? But, some clarifications would greatly be appreciated. had this boat on the water a couple of times already. will not get on plane. I suspect the max timing? But, boat motors are not my usual forte. I am mechanically inclined. I am an electrician by trade. Have a toy shop I work on 7.3 PS trucks and whatever else in. I have a bridgeport, a lathe, tig, mig etc... not bragging, just saying, I don't think this is over my head.. I just need a little guidance. Thanks in advance for any help, or pics or anything anybody can give me to get me and the wife on the water.

Pull throttle arm to full throttle and verify carbs open fully. Adjust main throttle stop so that the carbs are JUST hitting thier own little throttle stops. The idea here is that you want the screw stop and NOT the carbs acting as the "final stop" for your throttle lever.

Return the throttle to idle, carbs should be closed. Set all idle screws to 1 3/4 turns out from lightly seated.

Remove all plugs except #1, hook a timing light to #1. Then follow the narritive.

When the throttle is in the idle position the carbs should be fully closed and the ignition retarded. It is the amount of retardation that determines your idle speed and is set later with the idle stop screw.

Timing Event One - throttle pickup.
As the throttle is advanced, the spark timing advances toward TDC and then to before TDC. As the timing is just passing TDC the 1st (minor)throttle pickup should hit and start to open the carbs. Use the timing light. Adjust the tang or trigger screw to make this a reality. All of them are speced different, but if the 1st pickup hits at 3-4 degrees BTDC advance - you win. Use the timing light with a friend cranking it to complete this setting.

Timing Event Two - max advance.
As you continue to advance the throttle the timing will advance while the carbs slowly open a bit more. The next adjustment is max advance, this is the point where the distibutor (or trigger) can advance no more. Set the max-advance stop to 21 degrees for "direct charge" crossflow inlines and 34 degrees for the older plain vanilla crossflows. Use the light, - err to the side of caution.

Right after max advance, further throttle motion should cause the second throttle pickup to hit and open the carbs to full. You already set that -now verify it.

Leave the throttle cable disconnected and go to the water. Leave the boat strapped to the trailer and back it in so it's deep enought to run. Have a friend crank it while you operate the choke and throttle. Warm it up at 1500 rpms's.

When "warm" adjust the idle stop screw for about 800 rpm and then ajust your idle needle(s) in (one at a time) till the motor stumbles. Quickly backing it out 1/2 turn from "stumble" will usually save it from needing a re-start. Do that for all the idle screws. Re-set idle stop for 800.

Now have your friend put it in gear (make SURE you are on the transom NOT in the water) and reset your idle stop for as low as you can get it. 500-600rpm is great if your old reeds will let it idle that low in gear. Now, re-adjust the idle screws, in to stumble, then 1/2 turn out. When you've gone back and forth with that a few times and have it "perfect" - adjust each one out 1/4 turn.

Reset the idle stop so that it's about 700-800 out of gear and 500-600 in gear. Sometimes bad reeds won't let you get that low, you've GOT to get it under 1000 in neutral (worst case) to avoid beating up your lower unit when you shift into gear, even 1000 is "bad" but like I said "worst case".

Now adjust (and hook up)the throttle cable so that with the shifter in neutral, there is light to moderate pressure holding the throttle arm against the idle stop.

Take the boat off the trailer and go out in the water. Try the hole shot. If it falls on it's face try adjusting the idle screws out 1/4 turn at a time (all of them together) till you can get a hole shot. You can kind of do this on the trailer at the ramp, but it's not really safe for you, the boat, or the tow vehicle.

You're done.
 

Texasmark

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Direct charge is basically a different routing of the incoming fuel air to the combustion chamber......basically bore a hole in the side of the piston....as I recall....I had an I-6 115 hp D.C. Merc back in 1989......long time after origination of the 4 cylinder cross flow classic design. Direct charge entered the market on larger engines, not the classic. By the time you got new technology in smaller engines it was Loop Charging, the engines changed from 4 to 3 cylinders and still is today. Your classic, if truly the 4 cylinder classic, is cross flow.....all to my recollection.
------------------------
A couple of pointers may help you to play with things and get correlation between your engine and the Red instructions.

You have 2 things you are trying to accomplish: Position of the carb butterflies (1) and spark timing (2) vs throttle position as caused by movement of the engine throttle linkages controlled by the remote control cable.

You will have max and min stops on both. The full throttle (WOT) mechanical and spark timing limit screws are clearly marked. It's the low speed screw names that I can't help you with......but you can help yourself by playing with it and seeing what limits what. Like when you want the throttle arm stop screw to stop arm movement to the idle position before the tab on the carburetor hits it's stop. Then there is the timing stop screw for idle setting the timing slightly advanced (electrically).

The water testing is such that you get a slow enough speed in the water to be able to shift with minimal gear damage yet have enough rpms to keep the engine running after shifting. If this helps....... later engine instructions say to set the idle stop for 650-700 rpms with the boat in the water in F gear, boat in motion. That corresponds very well with the red colored recommendation, understanding that rpms will rise in N as would be expected with no load on the engine.

You need to have a good charged battery and as stated plugs removed from the engine to get good data from your timing light when setting timing. Good luck.
 

huntxtrm

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Awesome, thanks for the tips. I did find a faded sticker that says 36 degrees at cranking speed for max advance. That's about all I could make out on it. I have been looking at the linkage more. I believe I have it figured out. Going to shoot a timing light at it tonight. I believe all I need to change is max advance. Seems to idle fine, and go in gear pretty smoothly. Just no top end. Carbs are spotless. And adjusted to a good starting point. Even with a rough adjustment, I believe I should get more than 8mph. Checked plugs, by looking at them they look like they are firing. Not are fuel soaked, or fouled. I'll be fishing while fixing on it.
 

Texasmark

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Cranking rpms need to be around 200 so you need the fresh battery, plugs out.....reason is the electronic signal may not have as steep a leading edge if the speed is too slow....it's a magnetic thing and the pickup is magnetic to electrical coil (electromagnetic impulse). Voltage output is proportional to the inductance (gauss of the magnet and number of turns of wire) X rate of current rise vs time: V = L di/dt. The slower the cranking speed, the slower the magnet passes the coil, the smaller the pulse meaning the slope on the leading edge will be shallower meaning your timing will be delayed and your setup may look good at cranking speed but would be too fast for you at WOT. Too fast leads to pre-ignition problems for a given gasoline, like the recommended 87 octane. Pre-ignition can punch holes in pistons.
 

huntxtrm

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I will do the crank setting to get on the water. Then I will check it on the water at wot. I always run premium in my boats, just cause gas these days is crap. Thanks for the advice
 

Texasmark

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I will do the crank setting to get on the water. Then I will check it on the water at wot. I always run premium in my boats, just cause gas these days is crap. Thanks for the advice

Keep us posted,
 

huntxtrm

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Well, set the cranking timing. Still not much power. Little better. Wife is terrified of me timing it while running across the water. Gonna have to get a buddy to go with me.
 

racerone

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Facts.------These linkages do not go out of adjustment as a rule.-----How did this motor run for you last year ?------Have you done any simple trouble shooting for lack of power ?----Start with a compression test.----Post your numbers.----Does spark jump a gap of 3/8" (1 cm ) or more on all leads , yes or no ?-----Checked the exhaust tuner for blockage ?----Changed water pump impeller recently ?
 

huntxtrm

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Facts.------These linkages do not go out of adjustment as a rule.-----How did this motor run for you last year ?------Have you done any simple trouble shooting for lack of power ?----Start with a compression test.----Post your numbers.----Does spark jump a gap of 3/8" (1 cm ) or more on all leads , yes or no ?-----Checked the exhaust tuner for blockage ?----Changed water pump impeller recently ?

This boat is new to me. I did do a compression check(even numbers on all cylinders, 120ish if i remember right), spark test, rebuilt the carbs, replaced the fuel lines fuel filter, and waterpump impeller. This was done a year ago. Has been taking uo floor in my shop since, now I am back working on it. Boat had been sitting up a year or 2 when I got it. I was told. All good. As far as the exaust tuner, I dont know what that is. The reason I suspect the timing, is the throttle plate was shade tree'd. So I am guessing they messed with the sync trying to get it to run correctly again. I figured, worth it to go through the sync procedure, just to make sure. The screw had broken off at the tab, and was redrilled and tapped lower on the bracket. The screw was then bent up to engage the throttle. I have a book on it now, going to try the entire sync procedure this weekend. While the wife isnt looking. Lol
 

huntxtrm

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This is the shade tree fix that was in place
 

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huntxtrm

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Well, took it to the lake this morning for a little test and tune, and a lityle fishing. Didnt make it off the trailer! Fuel bulb decided not to pump up. Removed the cowl, fuel squirtin out of the vent on lower carb. Figured the fliat somehow got trash in it? I did replace all fuel lines, carb gaskets, filter and pump components a while back. So, I doubted that. Pulled the carbs. Float on bottom carb was full of fuel. Lol, I will tame these gremlins eventually! New floats getting ordered for both carbs!
 

huntxtrm

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Charlie had them in stock! Got them installed! Tuned! Test and tune and fish in the morning! Again! Fingers crossed.
 

huntxtrm

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Well, back to the drawing board.lol. did catch a few kitty catts, but a storm blew in on us. Dudnt rwally get a chance for much trouble shootin. Moved timing advanced a little, seemed worse. Did not get ouf the timing light. Because of the rain. Going the other way with it next. Going through the sync again in the shop, and crank timing. See what happens.
 

huntxtrm

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I had 18mph at one time. It is throwin helluva fire on all 4 cylinders cranking. Jumps a 7/16" gapper blue and hot. Could it lose fire under a load?
 

racerone

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Timing on these motors does not go out of adjustment.-----Look up / learn about crankcase compression / reed valves and exhaust tuner !
 

huntxtrm

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Ok, i will. But, as I said. Somebody messed with the timing. Before me, they hade the throttle plate second pick up screw rigged up. It was a shade tree fix. I did recheck compression today. #1 115, #2 115, #3 115, #4 110. I also double checked all the sync. Up to 30 degrees while cranking. Hopefully it wont rain me out tomorrow night, i can adjust carbs on the water, and see what happens. I will take your advice and look that up though.
 

racerone

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Hint----You can NOT find a broken / damaged / stuck open reed valve with a compression tester.
 

huntxtrm

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Hint----You can NOT find a broken / damaged / stuck open reed valve with a compression tester.

Good info. I will check that out. Thanks racerone. I do appreciate the help. Just like dirtbike reeds, laying flat, they are good? Of course, petal missing no good. No gap under petals? Wonder is thete a way to check them, without yanking the carbs again. I will look in my manual also. Maybe some "old hand" trick not in the manual would be helpfull though.
 
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