mercury50 4-syl. virker som om den holder igjen

[selco15]

hei jeg har også en mercury50 fra 79 med fire cylinder. den sitter på en selco 15 motoren fungerer kjempefint men virker virker som den vil ha mere turtall på full gass. virker som den holder igjen litt. har kontr at spjeldene på forgasserne åpner helt og det gjør dem. har også tenkt og kontrolere tendningen og få justert den. stå i verk hanboka at den akal være på 32 grader ved ca halvt på drag. kan den ha noe og gjøre med at motoren liksom holder igjen. og den må vel justeres da motoren har pådrag slik at tendingen er på maks. hvordan gjøres dette på enkleste måte. fint om noen kan hjelpe meg...

[Droll]

Hentet dette ifra et annet forum, er på engelsk, men burde ikke være noe problem.

Er skrevet og postet av en guru på disse motorene Wayne Canino, CC-marine.

 

 

 

Timing and Sync of Merc Inlines (to 1988)

__________________________________________

Manual specs are different for each but this is close enough to get them all REAL close. This assumes nothing is broken or "wrong" with it. This also assumes that the timing pointer is properly adjusted (if adjustable) to accurately read TDC of the #1 piston.

 

This basic procedure will work for all the 2/3/4/6 cylinder inlines from 1960 to 1988. It's not for the newer 3 and 4 cylinder loopers.

 

Engine off

 

Disconnect throttle cable

 

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.

 

-W

 

Din motor er en crossflow så max timing er 34 grader...

 

Sjekk også om du har rett propell, hvis motoren har sitti på en mindre båt før kan det hende propellen har for mye stigning, du bør kunne oppnå ca 5500 rpm med lett lastet båt .

Oppnår du ikke anbefalt turtall ( med frisk motor ) må du bytte til en propell som kan gi deg rtt turtall.

 

Lykke til

Arne Kjetil

Redigert 4.Juni.2008 av Droll (see edit history)

[selco15]

tusen takk for hjelpen skal prøve på den måten i løpet av uka. står det et sted på propellen hvor stor stigning den har?

[Daffy]

Ja det gjør det vanligvis.

for eksempel 10-3/8 x 14

da betyr det at den har 14" stigning.