1979 90 HP Mercury outboard Flooding issues

[CharlieB]

Re: 1979 90 HP Mercury outboard Flooding issues

You're thinking of a 4 stroke tach, an inductive pick-up on a plug wire as found on a 'tiny tach' works great.

Outboard tachs are a different breed, sort of a pulse counter, driven off the grey wire on the regulater/rectifier.

Any inductive will work, just need to remember that it is a 2 stroke, a 4 stroke inductive will read twice your actual RPM.

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

Good to know, thanks for the reply. Here is the latest; I went to start the boat again and for some reason it wouldn't start. I checked timing, spark, fuel and everything seemed correct, so I started checking all the Ohmic values for everything listed in my manual, everything from the stator, trigger and on to the coils and everything checked out good except the manual says that there should be no continuity between the coil tower and either the positive and negative coil terminals (using the R x 1000 range) and I ended up with .9 Ohms (which equaled 900 Ohms on the setting I was reading) and the next check was the same results "between coil tower and powerhead ground" on the R x 100 scale (900 Ohms again) and I am not sure what that means??? The engine would still not start and it was getting late. I tried one more thing, I sprayed the smallest amount possible (less than a half a second on the nozzle) of starting fluid and cranked the engine and it fired up as if the engine was brand new, I checked the timing and it was at 0 degrees and when I advanced it just until it made contact with the carb throttle lever and then it read 4 BTDC (perfect) I turned the engine off and checked the max advance 21 BTDC (perfect). While it was running I did have a house hooked up to it to prevent damage to the engine and I never ran above idle with it hooked up to the house. Tomorrow I will check everything and see if I can continue to set the idle speed using my automotive tachometer to the rectifier and see if I can't finish this thing up before the end of the day. Thanks again for all who have helped.

 

[Chris1956]

Re: 1979 90 HP Mercury outboard Flooding issues

That automotive tach will not work. Spend the $70 and get one for the dashboard. You are going to want to know your max RPM, when it comes time to select a prop. Get a waterpressure gauge while you are at it.

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

Thanks Chris, do have any recomendations as to which one would be best for my application? I will have to get one as soon as I can. Also the same goes for water pressure guage. Thanks again. I got the boat running again without priming it, I still need to tweak on the carb adjustments a bit more.

 

[Chris1956]

Re: 1979 90 HP Mercury outboard Flooding issues

Popular aftermarket gauges are made by teleflex and faria. I think the difference is appearance and perhaps cost. You can buy a set of gauges (fuel, tach, speedo,voltage) for an outbaord, and save a few bucks. The water pressure gauge usually does not come with it....

These are avail most anywhere

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

I still haven't been able to get the boat to the water, but it will happen by this weekend. Since my last post I have adjusted the carbs open another half a turn (now open 1 3/4 turn from lightly seated) and the boat starts up without the use of anything other than the choke and after it warms up a few minutes, if I turn it off and start it again (even after a few hours) it starts right back up by barely turning the key at all. I am heading out today to buy a used tach ($5) from a friend of mine who has a couple of older ones and said that either of them should work fro my application. It is supposed to be hot this weekend and I plan to get out in the water and finally do my final adjustments on the engine. I am extremely happy at all of the help in this forum and I have become very intimate (mechanically not sexually) with this engine. I was very aprehensive about starting this project, due to my limited experience with marine engines, but now I have a firm grasp on the concepts and a lot more confidence in my ability to tackle anything related to my boat. Thanks again for all of your help, guidance, suggestions and expertise. I will have another post to wrap things up after this weekend.

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

Ok, so today was supposed to be the day I got to finally finish this project, after several postponements (due to family illness), I was heading out to the water. I picked the boat up from storage and tried to start it, but the batteries were slightly low, so I charged them and with very little coaxing it started up just fine and proceeded to run great while it was warming up. About 2-3 minutes later it died as if someone had turned the key off (no warning). So I tried to start it but no matter what I tried it still wouldn't start, so I started checking all the obvious stuff, battery connections, fully charged battery, fuel, timing and that is when I noticed I have no spark! I began to investigate. Current was flowing to the starter, the Ohmic values from the stator and triggers were perfect. I had left the timing light attachted to #1 and tried cranking it, nothing, #2-6 nothing. So I continued on to the coils and after messing around a little while I had spark and it almost started, but shortly after nothing. I checked all the wires again with the timing light and nothing was there. I checked my timing light on my car and it works fine. I am begining to think that it has to be a short somewhere, but I am not sure where. I have poured over my manual (keeping an objective mind) but the only questions that I have are. How do I check the mercury switch and does my engine have an idle stabilizer (IS)? I can't find one any where on my engine (IS), but the manual eludes to the fact that there probably is one there. All of my engine technical data is in the prior threads. I hope someone can help point me in the right direction as I am now more frustrated than ever. I wont get another chance to look at this thing until Sunday afternoon at the earliest, but I will check back from time to time to see if any one has any suggestions for me. Thanks again.

 

[CharlieB]

Re: 1979 90 HP Mercury outboard Flooding issues

First thing to check is to UN-plug the black wire with the thin yellow trace from between the ignition module and the engine wiring harness, now retest for spark.

If you now have spark then you need to test the ignition switch for a short, killing the ignition. Un-plug the black w/yellow wire from the ignition switch, (re-plug it at the ignition module) and test spark again. If you now have spark again, I would seriously suspect the ignition switch has failed.

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

Charlie B, You are the man! I went and did exactly what you told me to do and I had spark both ways and without even trying to get it to start, it fired right up (I did have the water house hooked up to it) of course I couldn't get it to shut off. I disconnected the fuel line from it and it ran out of gas within a minute or two (hopefully this won't hurt anything electrically). I am going to order the key switch today. I will post my results when I am done. Thanks again.

 

[kdenfan]

Re: 1979 90 HP Mercury outboard Flooding issues

I received the switch today and I will put it in this weekend, but there is only one problem, I am not positive which wires go exactly where on the new ignition switch. The new switch has 5 terminals and they are labeled as Battery, Solenoid, Magneto, ACC and Ground. The ground is obvious and I believe the Battery goes to the Red wire on the wiring harness, but the other ones I need answers on. My Mercury is an L6 90HP 1979 (it is listed in my manual as 1979 only) it has the orange color wire going to the Mercury switch and switch boxes and not the yellow and black wires found in other years.The old switch isn't labeled the same and I really want to make sure that I get this connected correctly the first time (no electrical fires). My old switch has 7 wires 2 white (I believe acc's), 2 black (ground), a yellow ( I think this one is the solenoid), Orange (maybe Magneto???) and the red(battery). Can someone please verify these for me and let me know if this is correct. Thanks for all of your time and help I do really appreciate all the feedback.