Merc 140 starting issue

[jf3233]

Hello all, new to this board and boating in general. I have a 1980 merc 140 GM with a type 1 drive. Just got done going over boat. I replaced all bellows, sender switches, plugs, wires, fuel filters, lower shift cable, all fluids. I got the boat about 1 month ago and took it for a test. Ran fine but had some leaks through a depth finder wire. While out it ran great until I tried to start it later in the day. Would turn over but just not catch. This is why I went through it and checked everything. On to tonight I water tested it again. Fired right up and ran great. I had gone through and checked all wires, reset idle, choke and did above work. Same exact thing tonight. Ran great for an hour. Shift cable was spot on along with idle. Docked the boat and attempted to restart, it cranks over well but would not catch. I eventually got it going but I'm confused. Why would this run so well and then go funny on restart. By the way it did the same thing hot or cold previously. I can not replicate this on muffs either?

 

[Bondo]

Re: Merc 140 starting issue

Docked the boat and attempted to restart, it cranks over well but would not catch. I eventually got it going but I'm confused. Why would this run so well and then go funny on restart. By the way it did the same thing hot or cold previously.

Ayuh,... Right at that point,.. Pull the sparkplugs,... are they firing,..?? are they wet,..?? Dry,..??
Are you advancing the throttle,..?? It's got a Carb, not Efi...

 

[jf3233]

Re: Merc 140 starting issue

Bond-O

Could not check spark tonight I was at a busy launch. Previously plugs looked good a liitle grey but not wet. Carb yes as you know. I prime twice on a cold start and leave it at 1/4 to warm up. When hot I just prime once and leave a 1/4 fearing I will flood it. I thought spark but why would it go intermittent? I do have electronic and no points, could the pertronix be going, coil going, I think I can rule out the starter if I'm not mistaken

thanks in advance everyone.

 

[Bondo]

Re: Merc 140 starting issue

I think I can rule out the starter if I'm not mistaken

Ayuh,... If it's turning over/ crankin' the starter is Fine...

try 1/2 throttle, without the primer shot on a hot start...

 

[jf3233]

Re: Merc 140 starting issue

I will give it a try tomorrow.

 

[jf3233]

Re: Merc 140 starting issue

So I pulled the meter out today to check some things due to my hard starts. Now I will admit I am a novice with the meter but anyway. With the key in run position I was getting 5 v to + coil. Full 12 V at the Slave. When cranking I was getting 9-10 V and when running about 9.4V. Wiring to coil is as follows with Pertronix. ignition. I have a y/p from + coil to starter and a brownish pinkish wire going into harness. On the - coil is the black from Dist and a grey wire. Grey wire looks to go to the shift interrupt. Ignition red wire is linked to a purple wire in the harness I assume is a switched 12V although not the choke wire as I do not have an Electric choke. Kicker there is one purple wire left hanging not being used I assumed was the resistive wire. Coil does say use external resistor. Based on the meter while running could the brownish wire be the resistor wire as the coil was at 9V. Then which wire is the tach? Other thing is with key in run like I said it was 5v then after running and being shut down I came back to test again and + coil was now showing 12v. I beleive my hard starting is intermittent low voltage to coil? As usual it did start idle and run fine on muffs.

Thanks in advance

 

[jf3233]

Re: Merc 140 starting issue

Ok I verified the grey wire on the -coil is the tach wire. The black one is to the dizzy. I have a p/y on the +coil along with what looks to be a faded pink wire (thinking resistive). Red from the the dizzy goes to a purple 12V switched. I physically cleaned every electrical connection on the boat and inspected. Battery cable good and bat tests strong. Choke is closing and opening correctly when hot. Run position shows 5v on +coil. Cranking shows about 10v on +coil and running shows about 9.4 on +coil. All appear within range? I do believe my hard starting is more about carb set up. Idle screws were way out of wack. On a cold start when you pump the throttle once you squirt fuel and engage the choke correct. If you pump more then once does the choke disengage? When pumping cold should I get two squirts of fuel or just one. I saw only one strong stream. It is running on muffs ok and restarted yesterday 20 times without problem. Issue is the basic idle set up in the manual will barely idle this thing out of water. Put it in the water and I am sure it will not idle well. I will bump it up to 800rpm and then adjust in the water I guess. Timing was checked and ok.

Any takers?

 

[DayCruiser]

Re: Merc 140 starting issue

Same problem as many are having here. Have you tried Stabil Ethanol treatment fluid? I have other things that won't run worth a crud once you try and start them after they already have been run awhile. I went to a higher octane and that fixed the problem. Hasn't fixed the boat problem. So I am thinking Ethanol treatment.
Key words. Runs well and then rest a short time and then hard to restart. Seems like we have a trend going

 

[jf3233]

Re: Merc 140 starting issue

No stabil but up North I made a point of filling up with ethanol free since this is a new to me boat this year. Yep seems like a trend. Or in my case a really old 1980 trend. Based on my inspection everything else on this motor has been maintained. I have gone through and checked everything with the help of this forum.