6.2 MPI Cranks but won't start.

[Merc4ever]

My 2001 Mercruiser 6.2 with only 280 hours on it was running fine a few days ago but today I turned the ignition on, heard the couple beeps along with the fuel pump running up to build pressure and stop. Then I went on to turn the key farther to crank it over but it didn't fire? Cranking great and it usually fires immediatly but it's not even trying to fire. I connected the code reader and had no fault codes. Lanyard is in run position, any ideas anyone?

 

[Merc4ever]

Also I'm not seeing any RPM when cranking is that normal?

 

[alldodge]

My 2001 Mercruiser 6.2 with only 280 hours on it was running fine a few days ago but today I turned the ignition on, heard the couple beeps along with the fuel pump running up to build pressure and stop. Then I went on to turn the key farther to crank it over but it didn't fire? Cranking great and it usually fires immediatly but it's not even trying to fire. I connected the code reader and had no fault codes. Lanyard is in run position, any ideas anyone?

Start with the basics, check for spark and fuel. Check fuel first because it's easy. Turn key to run and have a fuel pressure gauge on the Schrader valve, or push in on the valve and see if fuel sprays out. Watch your eyes and try to keep a rag over it a bit to catch spray.

Next check for spark with a gap gauge or next to the block

 

[Merc4ever]

I'm not sure where the schrader valve is on the fuel rail because I didn't see it. But I did hook up a timing light while cranking and it didn't blink.

 

[Merc4ever]

I put a meter on the red + and white - studs on the coil then turned on the ignition and had 0 VDC. I'm thinking I should have 12, but I do have 12 volts on the 2 red and purple wires on the back of the key switch and nothing on the yellow wire with red stripe (probably the accesory position but I'm not sure because a wire diagram on line shows it's start wire?).

 

[alldodge]

I put a meter on the red + and white - studs on the coil then turned on the ignition and had 0 VDC. I'm thinking I should have 12, but I do have 12 volts on the 2 red and purple wires on the back of the key switch and nothing on the yellow wire with red stripe (probably the accesory position but I'm not sure because a wire diagram on line shows it's start wire?).

The Schrader valve will have a tire vale steam cap on it. It will be on the fuel rail.

Pull the plug off the coil ( Red and White) and put your meter on the Red wire (+) and the other lead on a good ground. If you don't get 12V with the key turned to run, go find the fuse. The fuse will be around the main and fuel pump relays. Both the fuel pump and main power relays are the same and can be swapped with each other. Both the main and fuel pump relays have fuses.

The Yel/Red wire only gets power when the key is turned to start. This power causes power to be applied to the slave solenoid and the engine turns over. This power also goes through the lanyard stop switch. Since your engine is turning over this is not the issue.

 

[Merc4ever]

Thanks. I found that Schrader under that brass cap and lots of fuel pressure. I will pull that red wire first thing tomorow and hunt down that fuse if needed to see if it's the problem.

 

[oldsub86]

How about the safety kill switch?
My son's outboard would not start - just cranked fine. We discovered the little plastic tab had broken off and the kill switch was operating.
We got a new one and clipped it on, and it fired right up.

 

[UncleWillie]

I put a meter on the red + and white - studs on the coil then turned on the ignition and had 0 VDC. I'm thinking I should have 12, but I do have 12 volts on the 2 red and purple wires on the back of the key switch and nothing on the yellow wire with red stripe (probably the accessory position but I'm not sure because a wire diagram on line shows it's start wire?).

The Yel/Red is the Starter Power and will show 12v only while cranking.

No power to the coil is most likely the Lanyard/Kill Switch near the throttle.
It may look like it is ON, but it, or the wiring, may have a problem.
Check for 12v on both sides of it.

 

[Merc4ever]

Pull the plug off the coil ( Red and White) and put your meter on the Red wire (+) and the other lead on a good ground. If you don't get 12V with the key turned to run, go find the fuse. The fuse will be around the main and fuel pump relays. Both the fuel pump and main power relays are the same and can be swapped with each other. Both the main and fuel pump relays have fuses.

I didn't find fuses but I did find a 50 amp breaker near the relays and a 20 amp breaker bolted to the right exhaust, both were good (power on both sides).

I did find this morning that I have power on the+ red (coil) wire with key on when I test it using the battery's - negative but when I put the meter on the coils white - I do not, that's testing without pulling the wires off the coil studs. Maybe that indicates a bad ground on the coil?

 

[Merc4ever]

I bought a spark testor and set it to E for electronic, then I put it right on the coil wire and didn't get a spark when cranking or when shorting the - neg side to ground.

 

[alldodge]

I bought a spark testor and set it to E for electronic, then I put it right on the coil wire and didn't get a spark when cranking or when shorting the - neg side to ground.

Don't ground out the white/lt green coil wire. The white side of the wire is what opens and closes by the ECM much like that of breaker points.

You have power to the coil, when testing for spark, you either need to remove a spark plug wire and hold it close to a ground while cranking, or put the spark plug tester inline and verify for spark. The fuses will not look like fuses on the outside. You need to look for small rectangular blocks close by the relays with two wires coming out of them. One end of the block will open and inside will be the fuse. Are you hearing the main power relay clicking on? Whether you hear it or not find the two relays and swap them. They are both the same.

 

[agallant80]

I once spent a few hours trying to crank my boat over only to discover that the safty lanyard had come out.....

 

[Merc4ever]

Don't ground out the white/lt green coil wire. The white side of the wire is what opens and closes by the ECM much like that of breaker points.

You have power to the coil, when testing for spark, you either need to remove a spark plug wire and hold it close to a ground while cranking, or put the spark plug tester inline and verify for spark. The fuses will not look like fuses on the outside. You need to look for small rectangular blocks close by the relays with two wires coming out of them. One end of the block will open and inside will be the fuse. Are you hearing the main power relay clicking on? Whether you hear it or not find the two relays and swap them. They are both the same.

I found the 2 relays and I know at least the fuel pump relay is good because I can hear it build pressure and shut off. I must have a good fuse because I am getting 12 volts to the red wire.

I pulled the coil out (Merc part #392-805570-1) of the boat and have .8 OHM's on the + to - studs and wonder if I should try a new one? I will attempt to test it with a battery.

 

[Merc4ever]

I once spent a few hours trying to crank my boat over only to discover that the safty lanyard had come out.....

I'm thinking I wouldn't have 12 volts on the + side of the coil to ground if my lanyard switch was faulty.

 

[alldodge]

I found the 2 relays and I know at least the fuel pump relay is good because I can hear it build pressure and shut off. I must have a good fuse because I am getting 12 volts to the red wire.

I pulled the coil out (Merc part #392-805570-1) of the boat and have .8 OHM's on the + to - studs and wonder if I should try a new one?

Don't replace the coil, I don't think that is the answer. Swap the 2 relays and see if you hear pump come on again.

I don't see the lanyard as the issue due to it will crank over. The lanyard breaks the Purple wire coming rom the ignition, without it, no crank, no nothing

Edit: in your first post you said there were no codes. What did you use to read the codes?

 

[Merc4ever]

I have 10k ohms between + and the center distributor post but from what I have read it should be between 10-11k ohms so that is good.

I have heard when coils fail they usually fail hard like this one... appears to be dead, and my resistance was a low .8 between the positive and negative posts when you should get 1.5 or 3 ohms depending on type. Maybe when loaded up with voltage bad things are happening?

---

 

[Merc4ever]

Don't replace the coil, I don't think that is the answer. Swap the 2 relays and see if you hear pump come on again.

I don't see the lanyard as the issue due to it will crank over. The lanyard breaks the Purple wire coming rom the ignition, without it, no crank, no nothing

Edit: in your first post you said there were no codes. What did you use to read the codes?

I'm off to check the relay now, I used the plug in Mercruiser Scan tool to check for codes it said there was none.

 

[alldodge]

Here is the 555 manual for your engine. Down load and go to page 2A-12 and go thru the steps. It should lead you to your fault

http://www.blainehanson.com/Manuals/...iagnostics.pdf

 

[Merc4ever]

Here is the 555 manual for your engine. Down load and go to page 2A-12 and go thru the steps. It should lead you to your fault

http://www.blainehanson.com/Manuals/...iagnostics.pdf

Thanks, I swapped the relays and the fuel pump ran indicating 2 good relays I believe, (pump didn't run with the relay unplugged so you were correct).
Off to do some reading but I will keep everyone informed if I find the problem for future....