Trouble starting/staying started

[jayhawk]

Hi. I have a 1996 Mercruiser Alpha One 3.0 Litre LX that I'm having some trouble getting to start/stay started. Battery was just charged and I cranked and cranked on it but it wouldn't start. I had the air breather off and could smell fuel. Pulled one of the plugs and tested for spark. Appeared to be no spark. I pulled the lead off the coil and put a plug in there and still no spark. I have a Clymer Mercruiser manual and did the test procedures on the ignition coil and the pickup coil and those both passed. This has the EST ignition not the Thunderbolt system. After hooking everything back up, I tried starting it again. Finally, it started and seemed like everything was good. I let it run for a minute and then started putting the air breather back on it and as I was tightening the nut on top, it died. Took the breather back off. Cranked again. It started again briefly and now won't start again.

I'm not sure if the spark plug test works on the EST ignition, so not sure why it would show no spark but then start later. I'm thinking it might be the ignition module, but didn't want to throw money at it without knowing for sure. My manual doesn't show a way to test the ignition module. Does this sound like a likely culprit or just a bad ground somewhere?

Thanks for any suggestions!

 

[fuzzybob]

Re: Trouble starting/staying started

Welcome, If you go to the "adults only" sticky at the top of the forum page you'll see a trouble shooting guide for starting probs plus a lot more! Go down the list to number 9 and you can download the merc manual for your engine get the one for your out drive too. Good luck, let us know how you do

 

[jayhawk]

Re: Trouble starting/staying started

Thanks for the reply. I went back to that page and downloaded the GM 4 cylinder engines 1990-1997 pdf. I assume that the Mercruiser is a GM? I didn't see another manual for a 1996 engine and the diagrams in that pdf looked accurate, so I went ahead and used that.

First, I read Don S's post: HOW TO: Troubleshooting your engines starting system. I followed those tests and all of them succeeded. So, I moved on to the test procedures in the manual.

1. First, it mentions that you should disconnect the tach terminal. Is that the tachometer on the dash? If so, does it matter which wire you disconnect?
2. I didn't disconnect it and proceeded. I got no spark on any of the plug wires or the wire coming from the coil. I got 10+ volts from the "C/+" terminals on the distributor harness.
3. It then said to hook up a test light to the tach terminal. Which terminal would that be? Is that a terminal on the tachometer on the dash or is there a special tach connector? I didn't see anything in the pdf about the tach terminal.

It actually fired up again, but I didn't have the muffs on it, so I shut it down to put them on and hook up the water. It started again, but I had the throttle way up and when I backed it down, it died and wouldn't start again.


Thanks for any assistance.

 

[jayhawk]

Re: Trouble starting/staying started

I suppose it would have been a good idea to post the actual tests that I tried. The engine still cranks and I can smell fuel, but it just won't start. Doesn't even sputter like it's trying to start. Just crank, crank, crank. So I assume the starter is good and the fuel line is good. I'm honing in on the ignition system.

First I tried Don S's How To and performed the following tests:
1. Test light clip to ground, touched terminal B of the ignition switch. Light came on.
2. Touched terminal S, turned key to Start. Light came on.
3. Went to engine compartment. Clip to ground, touched terminal C of slave solenoid. Key in Start position. Light came on.
4. Touch terminal A of solenoid. Light came on.
5. Hook clip to terminal A and touch terminal D. Light came on.
Stopped there since started appeared to be working.

Went to the EST Ignition System Check of the GM engine manual.
1. Pulled #2 spark plug, had someone crank engine. No spark.
2. Pulled #3 plug, had someone crank. No spark.
3. Pulled plug wire off distributor(other end to coil), put a spark plug on it and cranked engine. No spark.
4. Disconnected distributor 2 terminal "C/+" connector. Tested voltage of both terminals with ignition switch On. Got 11 volts on both.
Stopped here. It said next to test the voltage on the tach terminal to ground, but wasn't sure where to check that. If it's on the tachometer behind the dash, which terminal? There are three terminals on the back of my tach.

Hope that helps. It seems like it will start up once after it's sat for awhile, but then dies pretty quickly and won't start back up until the next day. Not sure if anyone has seen that kind of behavior before.

Thanks!

 

[rocket350]

Re: Trouble starting/staying started

May sound stupid, but are you grounding the plugs and wires to check for spark? Just sounds weird how you say no spark, then she starts....

Pour 2-3oz of fuel down the carb and she if she'll start. The fuel system will give you all kinds of problems if it sat and was not maintained. Check the filters, old gas etc. The carb will give you all kinds of problems if it is not clean.

I beleive the grey wire off the coil is the tach.

 

[jayhawk]

Re: Trouble starting/staying started

No, doesn't sound stupid at all. I thought you held the spark plug near a ground and looked for the spark. I was holding it close to the motor lift(where if you were gonna pull the engine, you would hook an engine hoist to) on the top of the engine by the distributor. Apparently that wouldn't work? If I touched the plug to that would it provide a good ground to check for spark or do you ground it somehow?

I did try pouring some gas right into the carb and trying to start it and it wouldn't start. Didn't even act like it was trying to start, if that makes sense. You can tell when it's trying to catch and start, but it doesn't seem like it's kicking at all. Just cranks away.

 

[fat fanny]

Re: Trouble starting/staying started

Jayhawk I had a similar problem w/ my 95 3.0lx. Start with scuffing all your pickups on you distributor cap and rotor, check the continuity on all your plug wires(wiggle them as you perform the test) pull you your ingnition module and take it to Napa they can cycle test it to see if it,s heating up and losing operating capability I had mine tested and it would only cycle 1 ou of 3 times I bought the GM replacement mod a little pricy but problem did not reoccur. This may not be your issue but it worked for me the intermitent issues are always the weekend killers. Good luck hope this helps.