Goes dead when motor put in gear

[jmbwest]

I just put a new fuel line and plugs on my 1983 80hp mercury. I went out to the river today to run it and the motor would throttle and run fine but when i put it in gear the motor would go dead. Could this be the power pack went out or just a case of bad plugs?

 

[basser#9]

OR STATER? I HAD SAME PROB YEARS AGO WITH A 75 HP MERC ? JUST MY 02. emoScratch HOPE IT ISN'T

 

[jmbwest]

It only goes dead under load. If i hook up water hose attachment at home will do fine. Hope that i even giving enough info to help someone give me a definitive diagnosis. Thanks for the info though barrer9.

 

[JDK]

sounds like a power pack i was having that same issue... send wrenchin a pm hes the man

 

[wrechin2]

Could be running on 2 or 3 cylinders and not enough to stay running in gear. Funny thing about a 2 stroke is they will run fine unloaded on the hose. I have taken a V-6 and pulled all plugs except 1 and it will run on just 1 cylinder with the other 5 out of course put in in the water and it would die as soon as it would engage as it is set up for 6 cylinders to be pulling the load. </p>

Plugs are a simple and cheap first test. The stator on that is split into 2 sections. Both sections have low and high side windings. If the low side windings are bad on one side, it is running on 2 and if the low side on one is bad, it will run on all 4 above 3K. Can be running on 3 if a switch box is bad. I have also had the wiring going from the pack to the coils to break under the top plate. These are easily tested with a Peak Voltage Adapter. Which I have and so will any dealer.</p>

 

[M GO BLUE]

...if it didn't have the problem before you changed the plugs, I would go back and verify that all plug wires are routed correctly and connected to the proper plugs/cylinders

 

[wrechin2]

It was late, last thing I read was bad plugs. Didn't realize he just put them in. </p>

That is a good ideal but they way the plugs are mounted, you would tell it very easily as one wire would be on top of another to cross it. They have a mount that 4 wires come out of. They are about 1/4 away from each other in the mount. You could simply install the old plugs and see if it has changed. </p>

Do you have a timing light?? You can see if all 4 are sparking. Will not tell you how much voltage is passing, just that voltage is present.</p>

 

[jmbwest]

Just got back from the water and the motor is still doing the same thing. I put the old plugs back in and it still went dead.

 

[Bubbakat]

Which line did you replace and why.

 

[jmbwest]

I replaced the line and from tank to motor because the last time i had it out i had a hard time getting the bulb to prime. Could it possibly be fuel pump going bad and not delivering enough pressure to run under a load? Since it ran fine the last time i had it out and it ran successfully.

 

[3391]

I would definitely check you fuel pump diaphram. When they split the motor will still idle but when loaded the engine just starves out.

 

[Bubbakat]

Also look at where you hook it to the tank and make sure it connected good and at the motor also. If you use the metal type clamps with a screw to tighten them yp then one could pinch a hole in the line and suck air. If it has a check valve where it turns and goes in the tank take it off and throw it away. While your there take the pickup tube out of the tank and see if it has devoleped a hole or stopped up.

 

[jmbwest]

Thanks for the tips. I will be checking those lines this weekend and trying an electric fuel pump. Will post results later. Any more tips will be greatly appreciated.

 

[wrechin2]

If a fuel pump is rupture it may flood one cylinder. You should be able to see lot more fuel in one cylinder. You will also be able to feel it in the bulb as it will never get "hard" all the way. Don't put a electric pump on it, If it is a ruptured pump, you will only make it worse. If it idles all day long in the water and dies only when you put in gear, more than likely not a fuel issue as the pump would need to fill up the carbs.

Simple test on fuel.... pump the bulb just after it dies. If the bulb is still firm, you can rule out a fuel issue for the most part. If you have to pump it several times to get it back "hard" then you more than likely have a fuel issue.

Electronics can do that. Run perfect one time and next time you take it out it has a failed electronic.

Simple spark test.....If you have a timing light, simply put it on each wire and see if all 4 have spark. This can be done on the hose in your driveway. If spark is present on all 4, then more than likely a fuel issue. If you are missing spark on any of them, you have a electrical issue. The tool I use to test spark also load test the coils to see if are weak. But a timing light will give you a indication if they working.

Just my thoughts.

 

[jmbwest]

Just got throught testing on motor. I could not get timing light to work right but i used what is called a smart tach and it showed spark on #1 and #2 but no spark on 3 or 4. So does mean it is power pack or is there another way to test it?

 

[wrechin2]

It takes a special tool called a peak voltage adapter (also called DVA). I will make it easy.. Read the NOTE at the bottom of the first page (numbered page 53. You will only find out what it is by testing the voltages everywhere. Your engine starts at 1/4 down on the page. I will also attach it in PDF so you can read it.

 

[wrechin2]

Here it is in pdf form.

 

[gpreeves37]

I am having the same problem with a 1994 model mercury 150hp. I changed all the fuel lines adn the water seperater. I had a lot of rubber in the seperator. Rebuilt the pulse pump and I still have the same problem unless I keep both tanks full. I'm interested to see the cure to this problem. good luck

 

[wrechin2]

Yours has the ADI (alternator driven ignition) ignition like this one. The difference is you have 2 switch boxes where this one has 1. The cure for this one may not be the same as yours. Same thing, yours needs to be tested with a peak voltage adapter and see what has went bad. The other way is costly. The stator on yours is a 40 amp and is $440. That is a very expensive "TRY"

Where are you located?? gpreeves37

 

[jmbwest]

Can i use a regular volt meter or does it have to be a dva?