3.0 mercruiser starting issues, i know another one

[backwoods901]

I have searched and read everywhere on this place and have tried almost everything, this is anew motor and delco voyager system. I verified timing, tried a new coil rewired to ensure their was not a resistance wire to the coil. i also rebuilt the carb, everything rotates tries to backfire, I am going to replace the ignition switch and bypass the neutral safety switch and see what happens. I just for the life of me can not get this thing to start.

the boat is a 94 sea pro centra. i have 12volts to the coil, i hooked up my spark plug tester and am getting a orange spark.

fuel is no issue it sprays like it should and it is all new fuel in the system.

 

[alldodge]

tries to backfire

Backfiring is not good and most the time it means it out of time. Note the firing order and the rotational direction of the distributer

Firing order

 

[backwoods901]

sorry for the short post. i verified all the timing and firing order. this does not seem to be an issue anymore, it hasnt backfired today at all.

 

[backwoods901]

So this is a new motor from Michigan motors. has a delco voyager ignition system on it, I currently have rebuilt the carb and have begun troubleshooting the whole entire ignition system. I have a new key switch to replace in the AM i also am going to bypass what i think is the neutral safety switch, the switch that is on top of the valve cover. I am reading 12volts at the ignition wire to the switch (purple wire) the other one i am reading 0 volts at. I will take pictures and see if anyone can help with visual aid. I have 2 ground wires hooked up to both batteries coming attached to the flywheel housing. I also added a third attached to the valve cover to eliminate a ground issue. I bypassed the kill switch, along with unwiring the grey wire from the tach.

basically I am stuck at what to do next. there is not to much more to the ignition system on this boat. I am a diesel mechanic in the coast guard and i am very familiar with marine applications but this damn 3.0 is killing me, so are my four little ones waiting to go out on this thing.

this is the motor i purchased for the boat http://www.michiganmotorz.com/base-marine-engine-1967-current-replacement-p-8871.html

 

[alldodge]

This won't be the first time a new distributor module was bad. MM is pretty good at replacing them if found to be so. Here is a bulletin which has testing

http://www.boatfix.com/merc/bullet/90/90_15.pdf

 

[Scott06]

The switch on the top of the valve cover isn't neutral safety it is the shift interrupt that allows the alpha one to come out of gear. It grounds the ignition for a second so for testing you can disconnect it just won't come out of gear in the water.

 

[backwoods901]

This won't be the first time a new distributor module was bad. MM is pretty good at replacing them if found to be so. Here is a bulletin which has testing

http://www.boatfix.com/merc/bullet/90/90_15.pdf

replaced the pick up coil it was grounded out and giving me a reading of 5.4 ohms, i have a good clean blue spark from the coil but i can not get this thing to start. I am verifying timing. Is there anything i may be overlooking with this motor. I have bypassed the killswitch, i disconnected the tach and the last thing i could do is replace the ignition to see if that is causing the issue at this point its kind of a head scratcher. unless the new pick up is bad.

 

[backwoods901]

The switch on the top of the valve cover isn't neutral safety it is the shift interrupt that allows the alpha one to come out of gear. It grounds the ignition for a second so for testing you can disconnect it just won't come out of gear in the water.

ok thanks for that, I bypassed it for now trying to figure out what is wrong with it, the last option i have could be to replace the spark plugs and see what happens from there

 

[backwoods901]

replaced pick up coil, no luck, It has to be the ignition control module. I replaced plugs for the hell of it and I still had no luck.

 

[alldodge]

have a good clean blue spark

With you getting a clean spark the either the spark isn't making it to the plugs or you need gas. If you can get any kind of spark at the plug, then pour a bottle cap full of gas down the carb and try.

 

[backwoods901]

With you getting a clean spark the either the spark isn't making it to the plugs or you need gas. If you can get any kind of spark at the plug, then pour a bottle cap full of gas down the carb and try.

i thought that as well but when i pulled my plugs they were saturated in gas, i seem to be getting plenty of gas in the carb you can hear it dripping when i stop cranking it.

 

[alldodge]

i thought that as well but when i pulled my plugs they were saturated in gas, i seem to be getting plenty of gas in the carb you can hear it dripping when i stop cranking it.

OK, that is your issue. You want gas fumes not liquid gas. While gas is volatile its not so much that spark will fire it up. You need to rebuild the carb

 

[backwoods901]

carb was rebuilt, did I miss something in the rebuild? should I take it back apart and double check the work I did? any specific things to check for?

 

[alldodge]

Float level, needle and seat
With plugs wet you should see gas dripping down the carb. Should also check the fuel pressure, if its over 7 psi then its to high

 

[backwoods901]

thanks for everything on this, I will check Wednesday when I get home from work and I will let you know the result.

 

[cdhunter]

Dumb question compresion stroke and number one are insync? I've seen many a distributor installed 180 out.

 

[backwoods901]

No Title

i verified timing and did everything i thought i needed to do to get this thing to run. i adjusted the float and fixed the fuel issue, then the engine was backfiring right out the carb i assumed 180 so i pulled the valve cover to verify TDC.

now all it does is crank, either the ignition module is bad or the pick up is bad from the store.

Any other ideas?

 

[alldodge]

Check for 12V at the positive side of the coil. When the engine cranks do you have spark from the coil or wires?

It could also be with the backfiring you were a little off, and now your 180 out. If the intake was closing as the crank was coming around, and then after it closed the timing mark came up your at TDC

 

[backwoods901]

Check for 12V at the positive side of the coil. When the engine cranks do you have spark from the coil or wires?

It could also be with the backfiring you were a little off, and now your 180 out. If the intake was closing as the crank was coming around, and then after it closed the timing mark came up your at TDC

i am heading back out to re verify i think i may have just thrown it 180 out. i have spark, used one of the originals off the old motor. I also misunderstood what it meant by pointing at #1 if im correct when i align the distributor. which ever way the rotor faces is where i should place my number 1 plug?

 

[backwoods901]

AllDodge thank you for all your help, i re verified timing and dropped her in and re adjusted the cap and, she started this time and she has cranked back up 3 times now. I have to fix a water leak, but i will be taking her out Monday for her first trip then hopefully with the family tuesday (work weekend). If there is one thing i wish the Coast guard would of taught me this far is carburetors and distributors, i know the insides and out of a honda 225 and mtus but this little 4 banger had me all confused.

again thanks for everything with this and my kids are super excited now