Mercury Ignition timing troubles

RICKRICK1

Ensign
Joined
Jun 24, 2002
Messages
926
Re: Mercury Ignition timing troubles

Glad you got it fixed, seems like all the little things add up on these motors. Not real competent on the newer motors (cdi, rectifiers and all) so followed you post. Again am glad you are up and running.
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

Hiya guys, Just came back from a long trip, and decided to take the 78 boat out, 90HP 6CYL, replaced the tach, and the voltage gauge, and to my dismal, found out the rectifier was bad, and the stator wires were fried, but patched with silicone.<br />Ended up replacing them both and the timing belt.<br />Is there a way to setup the WOT timing when the boat is out of the water and using a flush hose ?<br />I discovered the throttles were out of position.<br />My manual is kinda obscure when it comes to my s/n 4848057. It is a thunderbolt type II.<br />The shop says "it has to be out running full blast"
 

Hooty

Rear Admiral
Joined
Oct 2, 2001
Messages
4,496
Re: Mercury Ignition timing troubles

I don't know if there's another way to time that engine, other then under full load, or not. If there isn't, you can do it on the trailer. Just be sure the boat is secured to the trailer and can't move forward. Back it into the water far enough so the water inlets are submerged, crank it up and time away. <br /><br />c/6<br /><br />Hooty
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

That is to me the most creative and wizardly suggestion. I will try it out this weekend.<br />You win another star.<br />Thanks<br /> :)
 

Gold Bear

Petty Officer 1st Class
Joined
Sep 26, 2001
Messages
224
Re: Mercury Ignition timing troubles

xyphrx <br /><br />On your particular engine you can set the WOT timing using the muffs.<br /><br />Start the engine and disconnect the fuel supply hose, make sure it has run completly out of fuel. (Many suggest not doing this very often because right before the fuel runs dry the engine experiences a lean condition momentarily).<br /><br />Connect the timing light, move the controls to WOT, make sure the water hose is "on". Spin the engine over for just a moment and verify the setting. It helps to have someone hit the key for you, or use a remote starter switch. You should not have to turn the engine over for a long period of time, just long enough to see the setting. (You don't want to spin the engine over very long because the fuel /oil mixture is not present).<br /><br />Be careful in case the engine manages to start unexpectedly - you did run it dry of fuel right?<br /><br />Check you manual for timing settings. If memory serves me you don't want to exceed 21 degrees.<br /><br />Good Luck,<br /><br />Gold Bear ;)
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

Now I see why you are Golden Bear.<br />I followed your directions, and was able to set the iddle and WOT in just a few minutes.<br />Everyone has been very helpful.<br />I will keep the little boat for a while.<br />Again, thanks a bunch.<br />This little project is giving me the idea of pursuing a second career for my retirement.<br /> :) :)
 

Gold Bear

Petty Officer 1st Class
Joined
Sep 26, 2001
Messages
224
Re: Mercury Ignition timing troubles

xyphrx <br /><br />Thank you!! It is nice to get positive feedback.<br /><br />Best Regards,<br /><br />Gold Bear ;)
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

Guess what guys:<br />Everything was fine until I decided to run it before I went out; charged the battery, fired fine first time; and then the trouble began when I tried the second time an hour later. Would not fire.<br />Took out the plugs, and noticed that that there were signs of firing only on three cylinders ; the top three.<br />I then tested for spark and was little. Then I checked the coil disconnected from the engine, and found continuity between the tower and the both of the other coil terminals. My manual said it should not be any. I tested the trigger, and was within specs. I assumed the coil was on the blink. I had a couple of used coils I bought on the net and also they show continuity. Am I correct in replacing this item for a new one ?<br />What are the chances of the switchbox going bad ?<br />Do you know were I can find testing info for this box?<br />It is a 90HP Mercury 78, thunderbolt II, 6 Cyl in line s/n 4848057.<br />I am not throwing the towel yet. I go to get a fish. <br /> :confused:
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

I felt I had to report to you the successful results after my experimentation since you have been so helpful and kind to me..<br />I had replaced the rectifier, stator, switch box, coil, carburator kits, distributor brush and spring, tested the wires for continuity and spark.<br />First, I took out the spark plug wires, connected the ohmn meter, and jiggle the ends; guess what, some ends had became unsoldered where they attached to the threaded fitting.. I took the chance to resolder them; at 18 bucks a wire, had to try something..<br />It took a battery to go down, and still did not fire.<br />Then I rechecked the carburators for float adjustment, and for cleanliness of passages, set needles at 1 1/2 turns.<br />Checked fuel pump for flow while cranking, opened the carburator drain plugs, and I had flow thru the carbs.<br />Recharged battery.<br />Today, still did not fire, although all settings appeared correct.<br />Then I remembered that the last registration sticker on the boat was in 1999.<br />Something else had to be wrong.<br />As a last resort before I ditched the entire project, and thinking that I did not have a single SARDINE or MINOW to show for after all this months of sporadic grief, I stopped by the local auto parts store and got Carburator cleaner and starter fluid.<br />I tried the starter fluid using a couple of shots on each carb. intake, to no avail.<br />It appeared that the fuel was not getting to the spark plugs, since when I cleaned them and after a few cranks, there was no sign of carbon traces.<br />Theeen, I proceeded to squirt crburator cleaner deep into the carbs throats without mercy.<br />After a few cranks and taking the chance of burning the starter, IT SHOWED signs of gaining some spiritual strenght. What a relief !!! It appeared as it was firing the cleaner, or maybe some passages to combustion chamber had opened.<br />I tried a few more times, and after one hour of this, allowing sometime for the starter to cool down, IT CAME TO LIFE !!!!<br />The engine was firing and running at iddle smooth as a purring Largemouth Bass !!<br />I have not taken one of this engines apart yet.<br />Does anyone know the causes of this mistery ?<br />Your answer may help someone to try something new.<br />God bless; Thanks again for your patience.<br />Happy Memorial fish weekend I will catch one in your name. :) :cool: :p
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

I dont know how the little grren face got there. Please disregard. :)
 

tmcalavy

Rear Admiral
Joined
Aug 29, 2001
Messages
4,005
Re: Mercury Ignition timing troubles

Old gas turns to varnish and plugs/gums stuff up. Sounds like you had some in your carbs that the cleaner dissolved. Glad its purring for your now...take it out a run it.
 

jorenac1

Cadet
Joined
Dec 21, 2002
Messages
29
Re: Mercury Ignition timing troubles

Weeell, it ois my Merc 90, 6 cyl 1978 again, it appears as if the carburator cleaner worked out only for a short period, since now the engine won't start. All electrical systems and tsettings are correct, and carburators rebuilt.<br />It starts only with the help of the hitech carb cleaner.<br />I took out the plugs today and were filled with gum, sludge like stuff. Looked inside with flashlight and looks messy in there.<br />Shall I decarb using the Seafoam first,in the spark plug holes,flush it out by cranking, or and then try the famous Deep Creek thru the carburators throat after the Seafoam an sludge is removed ? Is it safe ?<br />Your input may take me out of the temporary insanity I have been going thru.<br />Thanks for reading my stuff; God bless.<br /><br /> :eek: :confused:
 
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