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1978 mercury 800 80hp timing issues

sorry, had a Dr. visit. I understand what your getting at now. I was gonna pull the plug wires as you suggested but at the moment it's raining and that's the last thing I won't to do on wet ground LOL.
 
If bleed restricters are missing it is a " huge hole " so to speak to the cylinder below.---------------Use a tooth pick as a probe to see if any are missing.-----------I install 8-32 stainless setscrews ( 0.035" hole ) on rebuilds, never fall out again.
 
racerone said:
If bleed restricters are missing it is a " huge hole " so to speak to the cylinder below.---------------Use a tooth pick as a probe to see if any are missing.-----------I install 8-32 stainless setscrews ( 0.035" hole ) on rebuilds, never fall out again.
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I was just reading another post you mentioned this on, so correct me if I'm wrong. are you saying to just plug the bleed restrictor holes?
 
no luck finding the gaskets locally. but I'm no stranger to making gaskets but dose anyone know the thickness of the Transfer Port Cover Gasket?
 
after wating 2 weeks for gasket to come in, I install 8-32 stainless set screws with 0.035" holes for bleeders but made no difference. still stalls out when put in gear.but just for the record it was 2 out of 3 bleed restrictors gone.
 
The additional load of a prop turning in water should slow an idling motor down by 50 -100 RPM.-----------Yours stalls so it is not producing the correct power to keep running.-----------Perhaps it is idling to slow initially.-----------Perhaps the carburetors are not " clean "---------------seen many tales of people on these sites taking carburetors apart 3 / 4 times before they finally " get it right "-----With the motor in nuetral and idling what happens when you turn in ( from 1-1/2 turn out from seated ) the slow speed mixture screws ( one at a time ) and what happens when you turn them out ???
 
racerone said:
The additional load of a prop turning in water should slow an idling motor down by 50 -100 RPM.-----------Yours stalls so it is not producing the correct power to keep running.-----------Perhaps it is idling to slow initially.-----------Perhaps the carburetors are not " clean "---------------seen many tales of people on these sites taking carburetors apart 3 / 4 times before they finally " get it right "-----With the motor in nuetral and idling what happens when you turn in ( from 1-1/2 turn out from seated ) the slow speed mixture screws ( one at a time ) and what happens when you turn them out ???
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well can't hurt to clean carb's again, I remember a heated solution we used to clean auto carb's long ago just can't remember the name but it worked well, strip the carbs and place it in the vat.
 
Laquer thinner does a number on old gas varnished fuel passages. I use it on all metal carb parts in an clean paint style can. Just use it outdoors since it is very dangerous...it will kill you if inhaled or it ignites.
 
guyjg said:
Laquer thinner does a number on old gas varnished fuel passages. I use it on all metal carb parts in an clean paint style can. Just use it outdoors since it is very dangerous...it will kill you if inhaled or it ignites.
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good choise and advice I'll give that a try.
 
Well guys after getting over surgery in both shoulders I’m back on my boat again. And after following all the good advice to no avail. I thought I had burned out my water pump when it stopped putting out water. So I pulled the foot to
find milky oil coming from the exhaust tube. Water pump was still good. So ether a blown head gasket or cracked head.
Either way it’s not good.
Just don’t see how it’s still got good compression, 130 to 135 all four cylinders.
But it may be that was what was causing all my problems to begin with.
 
There is no " head gasket " on that motor.-------Only a water jacket cover gasket.-------Milky oil in the exhaust is a common occurrance in a 2 stroke motor and very normal.
 
The distributor Mercs have a complicated advance mechanism. When the throttle is opened, the distributor goes from full retard to max THEN the carbs start opening. If you watch carefully, as you open the throttle, you'll see the distributor STOP at full advance while the mechanism contines to rotate, which opes the carbs.

What happens on motors that have sat around for a long time is that the grease in the mechanism dries out and freezes the mechanism, and when THAT happens, the carbs either don't open at all, or only partially.

So, here's what to do:

1. Make sure this mechanism is free. If not, remove it, dissaemble it, clean out the old grease, and reassemble with new grease. That's the only cure.

2. Study carefully the adjustment stops on the plate in front: Note the Max Spark Advances, and the Max Throttle Stop (carbs fully open). Be sure the carbs don't (or barely) start to open before the distributor reaches FULL spark advance. If not, welcome to Bog City.

3. Time it with a light. The best and safest way to do this it to remove the top carb's throttle cam arm (one screw). That way you can hold her wide open (about 3 grand) and get the timing perfect.

Do all this and she'll run great!

Jeff
 
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I'm thinking it's coil per cyl on a '78.Could be wrong.Back to clutching at straws,Is there by any chance a straight line and three dots on the flywheel? The straight line is the set mark and the three dots the timing mark when cranking.But that's on older 800's.Maybe the timing pointer is out of sync. There is a bit about it in the Seloc manual
 
You are correct; no distributor on that one. To time it, though, the best way remains removing the top carb's throttle lever (one screw) and holding the throttle open. The flywheel has degrees marked on it for timing. I think 23 ' max is what's called for.

Jeff
 
haventaclue said:
I'm thinking it's coil per cyl on a '78.Could be wrong.Back to clutching at straws,Is there by any chance a straight line and three dots on the flywheel? The straight line is the set mark and the three dots the timing mark when cranking.But that's on older 800's.Maybe the timing pointer is out of sync. There is a bit about it in the Seloc manual
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Yes havevtaclue it is coil per cylinder and no there is no 3 dot’s only lines and degree markings.
Think I will start from scratch tomorrow and check the Timing marker and go from there.
If I can’t find it this time………. I guess I’ll put it in the shop. (Lord Knows I hate That) may not get it back this summer. LOL.
Let yall know what happens.
 
Don't give up until you see how she's timed. Do it the way I explained above--easy to do--and that'll be out of the way. If it still runs badly, then you'll need to look at other things.

Jeff
 
well after looking very close... it looks as the ring bolts have been removed from the flywheel, now I have figure out it they were put back correct.
Talked to Mr. leon he doesn't recall ever having the motor worked on but broken paint on all the ring bolts tells me it has.
 
Well guys this is just an update. I ordered a new powerhead (new old stock) now I’m fishing again and runs great.
For the heck of it I split the old powerhead and found some reeds stuck closed and some had gaps a good 1/16 or better but I’m guessing that was the cause.
Now I think I’ll completely rebuild it while I can still get parts. But I would like to tell everyone who tried to help,,,,,,,Thank you.
 
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