3.0 Merc wont start please HELP!!!!

[mike_1984]

Ok, i have gone through the Clymer book, read all the posts, and checked everything i can think of and the boat wont start. I bought a boat with a damaged engine. I just bought another 3.0L Merc, alpha 1, serial number starting with 0A out of a 88 boat. I believe it has something to do with timing. I stabbed the distrib. at #1 cycl TDC, and the plugs are correctly connected. I am getting spark to the plugs (manually checked by holding the plug and turning it over.) I have tested the Shift interupt, (good) disconnected and bypassed (clymers manual) and connected it. ( no start) I have checked the coil, its getting power, and the purple wire is hot. The black connector is getting power to the two open terminals. I checked the pick up coil, not shorted. I have checked the lanyard, in run position. Gauges are lite and working. Tach does not read 200 when turning over though. ( book says it should read 200 rpm or more.) It just bounces off the bottom. Ive installed a new battery, and the boat turns over fine but will not fire. I have checked to ensure fuel is in the carb, accelerator pump is working. I have even tried the disconnect engine harness connector, put power to the coil, and jumped it to the starter. It just turns over. What oh what can it be. Ive been going at this for 2 days and have come up with nothing. Compress is 100, 120, 130, 120. Please help. Thanks mike

 

[Bt Doctur]

Re: 3.0 Merc wont start please HELP!!!!

Double check the timing at #1 TDC and the the firing order 1,3,4,2.
compression looks good, spark at the plugs is good,
is it gettting fuel????

 

[mike_1984]

Re: 3.0 Merc wont start please HELP!!!!

thanks for the reply, I have double checked the distib at TDC. I have pulled it out and re stabbed it, its at tdc on the compression stroke. Firing order is 1-3-4-2 starting with the front cylinder of the boat. Any other ideas? As far as fuel goes, it is spraying fuel through the accelerator pump. Good strong stream, and even got to the point of hittting it with some starting fluid. Got nothing.

 

[Bt Doctur]

Re: 3.0 Merc wont start please HELP!!!!

Not trying to be smart, but is the rotor turning in the correct direction in respect to the plug wire order. seems you have fuel, spark, and compression to where it should run.
Just a guess here but pull the valve cover and see if the valve train operates properly, valve open and close, etc.

 

[Don S]

Re: 3.0 Merc wont start please HELP!!!!

After you put the distributor in, are you sure the rotor was aimed at #1 plug wire? Did you try turning the distributor back and forth while cranking?
You might want to head up to the Adults Only sticky at the top of the forum and download the OEM service manual for your engine (#10) it may be that your Clymers manual has the direction of rotation wrong for your engine. Wouldn't be the first.

 

[mike_1984]

Re: 3.0 Merc wont start please HELP!!!!

Rotor on the distributor turns in a clockwise direction. (checked by turning it over and watching it.) When the distrib was stabbed, the #1 cylender was at TDC on compression stroke, stabbed the distrib with the rotor point pointed at the #1 cyclender. going in a clockwise direction, distrib cap starts with #1 (by the #1 spark plug) then 3 then 4 then 2. Valve terrain seems to be operating smothly, just lossened the rockers 1/4 turn to ensure no valves were hanging. Ive rotated the distrib cap while turning it over, in small increments, no luck. ( ive done it with the jumper on the distrib white wires and with out, and with the shirt interput switch hooked up, disconnected, and disconnected with the wire harness wires connected.) Checked spark on all plugs now, spark is good. Whats next? Thanks for your help guys, ive been working about 16 hours a day for last 3 days on this.

 

[mike_1984]

Re: 3.0 Merc wont start please HELP!!!!

ok, im a little confused now. The compression test read all cylenders over 100, now 4 days later i ran a leak down test, and its reading 60% leakage, on the best, and off the charts on the other 3 cylenders. ANy reason for this?
The compression check was done when we first got the motor, (its been sitting for several years, we sprayed some WD-40 in the cylinders before the check) NOw ive been turning the motor over for 4 days. What gives?

 

[Bt Doctur]

Re: 3.0 Merc wont start please HELP!!!!

Lets try the basic approach to timing a motor:
remove valve cover
identify #1 cyl. intake valve
rotate motor untill it opens (goes down) then closes(goes up)
this is #1 compression stroke
Slowly rotate motor untill mark is at "0"
drop dist in with rotor lining up with #1 plug wire
Should be able to run and then set timing with a light.

 

[blktout67]

Re: 3.0 Merc wont start please HELP!!!!

have you tried the cut off safety switch on the dash just a thought