1987 OMC 4.3 wont start after changing plug wires

[PaJon]

Hi every one. I have a 87 4.3 that sat for 5 years in storage. The motor ran good when it was put in storage. I changed the fuel filter, replaced points and condenser, set gap to .019, changed oil and filter, pulled the distributor and primed the oil pump. It started and ran. I warmed it up and checked the timing, set it at 6 degrees. Noticed that the engine had a miss. With the timing light connected I noticed that I lost spark to the plug whenever the engine stumbled. I changed the cap, rotor and plug wires, now it wont start, it just stumbles for a few seconds like its flooded. I pulled the cap and set number 1 to tdc and verified the rotor was pointing to number one. The intake and my manual both say the firing order is 1,6,5,4,3,2. I tried another cap, rotor and plug wires with no change. Im lost at this point. Its acting as if the plug wires are on wrong but i rechecked several times. Does anyone have any thoughts what i did wrong ?

 

[indybleck]

Re: 1987 OMC 4.3 wont start after changing plug wires

Look at previous posts, they will all say the same thing, check for spark from the coil, and also at the spark plugs. I have a friend of mine that had to make a new coil wire because it was a little short. Spark and fuel, check the plugs to see if they are gas saturated. That will tell you you have no spark. Good Luck

 

[libellav15]

Re: 1987 OMC 4.3 wont start after changing plug wires

check your tdc of number 1 pot is on compression stroke not exhaust - else you will be 180 degrees out and get the symptoms you describe

hope it helps

adam

 

[airdvr1227]

Re: 1987 OMC 4.3 wont start after changing plug wires

Agreed. Can't tell you the number of times a running engine was made to stop running by simply changing the plugs. Triple check the firing order.

 

[bruceb58]

Re: 1987 OMC 4.3 wont start after changing plug wires

Agree with previous posts. You could be at TDC and be at the top of the exhaust stroke and not the compression stroke.

 

[RogersJetboat454]

Re: 1987 OMC 4.3 wont start after changing plug wires

check your tdc of number 1 pot is on compression stroke not exhaust - else you will be 180 degrees out and get the symptoms you describe

hope it helps

adam

+1^^^^

This is where a sharpie marker can be an indispensable tool to mark # 1 on the old cap before you pull wires.

Other though... you are doing the firing order on the cap in clockwise rotation, right?

 

[libellav15]

Re: 1987 OMC 4.3 wont start after changing plug wires

Other though... you are doing the firing order on the cap in clockwise rotation, right?

great addition - good point

 

[PaJon]

Re: 1987 OMC 4.3 wont start after changing plug wires

It was on compression when I set it, rechecked several times. Had my finger over number 1 plug hole while turning it. I also did set the wires with a clockwise rotation. I keep thinking I missed something but have redone it several times now. I have spark from the coil wire to the cap. I had another friend recheck it also. Im half tempted to set the wires with a counter clockwise rotation just to see what happens. I pulled the plugs tonight and checked them, they are wet with fuel, but if its not firing at the right time they should be. I pulled the top of the carb off just to see if the float was sticking but it looked fine.

 

[bruceb58]

Re: 1987 OMC 4.3 wont start after changing plug wires

Unplug your ESA just in case that is the culprit.

 

[libellav15]

Re: 1987 OMC 4.3 wont start after changing plug wires

have you changed the condensor? i think you guys call it the capacitor?

 

[libellav15]

Re: 1987 OMC 4.3 wont start after changing plug wires

sorry - just read OP and see that you did change the condensor.

if it were me i would put the old condensor back in as it was proven as good

i've had a couple of 'new' condensors that are defunct out of the box

 

[bruceb58]

Re: 1987 OMC 4.3 wont start after changing plug wires

I would try the old condenser as well.

 

[PaJon]

Re: 1987 OMC 4.3 wont start after changing plug wires

I'll try unplugging the esa and try the original condenser today. I ran a jumper from the battery to the coil, still no start. What bothers me is that I have spark if I open and close the points manually, it's still acting as if the wires are wrong.

Thanks to everyone for the ideas so far. I'll keep you posted.

 

[indybleck]

Re: 1987 OMC 4.3 wont start after changing plug wires

Roll it over with the cap off and see if your points are working.

 

[bruceb58]

Re: 1987 OMC 4.3 wont start after changing plug wires

Also, what is the dwell reading while you crank the engine?

 

[Bridar]

Re: 1987 OMC 4.3 wont start after changing plug wires

Check your new rotor against the old one. I've been given the wrong one from the dealer before where it fit on the distributor shaft pointing 180 degrees different from the old one.

 

[PaJon]

Re: 1987 OMC 4.3 wont start after changing plug wires

Good morning everyone. First I wanted to say thatnk you for all the thoughts on this problem. I was able to get it running yesterday. It was something stupid and simple that I didnt even think off. The clamp and base of the dist had some corrosion on it and caused grounding problems. It must have been just enough connection to spark if I opened the points manually but not for it to run. I cleaned the base and clamp and she runs again. This is a great forum and its nice to see so many people helping some one out. Thank you all again.

 

[john cole]

Re: 1987 OMC 4.3 wont start after changing plug wires

thank for telling us how you found the problem, i never would have thought of a grounding issue at the base of the distrubitor.

 

[libellav15]

Re: 1987 OMC 4.3 wont start after changing plug wires

welcome welcome welcome

now get out and get it wet

be safe

adam

 

[PaJon]

Re: 1987 OMC 4.3 wont start after changing plug wires

She is back in the water and running great. View attachment 117895