MerCruiser 140 Stalls While Accelerating

[andyspoppa]

Re: MerCruiser 140 Stalls While Accelerating

Two things I would look at...if the electronic ignition unit is for vacuum advance...
And you are using it on a non vacuum setup...you wont be able to advance the timing!
Also start it up in the dark...see if you have spark leaking on your distributor cap. I suspect ignition...not fuel.

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

Two things I would look at...if the electronic ignition unit is for vacuum advance...
And you are using it on a non vacuum setup...you wont be able to advance the timing!
Also start it up in the dark...see if you have spark leaking on your distributor cap. I suspect ignition...not fuel.

I'm not sure what you mean, re: which setup? The electronic ignition is designed for this engine (1985 MerCruiser 3.0L 140). I rechecked, and reset the timing. It idles fine, give it throttle tho and it stalls. Thanks.

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

After hunting down a bad ground, I'm back to the original problem (thread title). Rechecked and reset timing, idles fine, smooth but stalls if you give it throttle. Down to my last option (as bond-o so nicely put it) a rebuilt carb. $$glub, glub$$

Thanks all for your advice and feedback!

 

[slothman]

Re: MerCruiser 140 Stalls While Accelerating

After hunting down a bad ground, I'm back to the original problem (thread title). Rechecked and reset timing, idles fine, smooth but stalls if you give it throttle. Down to my last option (as bond-o so nicely put it) a rebuilt carb. $$glub, glub$$

Thanks all for your advice and feedback!

carb rebuild is easy, just take your time. Make sure the float is set and all the jets are clean. A clogged jet is most likely the problem. $50 for a rebuild kit, tops....

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

Thought about that, but I need to know for sure. I just want to bolt it on and go. No second guessing myself on adj or measurements, etc. Summer's almost gone!!!

 

[slothman]

Re: MerCruiser 140 Stalls While Accelerating

Thought about that, but I need to know for sure. I just want to bolt it on and go. No second guessing myself on adj or measurements, etc. Summer's almost gone!!!

why not have a shop rebuild it? that should still be cheaper than a brand new carb.

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

thanks!

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

why not have a shop rebuild it? that should still be cheaper than a brand new carb.

I found a local shop that rebuilds them, but also found an exchange that would be faster for just a little more... thanks!

 

[PoppasWellcraft]

Re: MerCruiser 140 Stalls While Accelerating

I'm not sure what you mean, re: which setup? The electronic ignition is designed for this engine (1985 MerCruiser 3.0L 140). I rechecked, and reset the timing. It idles fine, give it throttle tho and it stalls. Thanks.

Hey guy,
When shopping for an electronic conversion kit for the distributor...there are two types on the market. One is for a distributor with vacuum advance and there is a kit for engines with Mechanical Advance (fly weights) If the PO had the same trouble and he had installed a kit for the distributor...did he get the RIGHT kit? :grumpy:

Simple test to see if you are getting the fuel: Take the breather off...have someone advance the throttle quickly...if you see a good squirt of fuel then Carb is NOT your problem. (Do this with the engine shut off)

If the ignition kit is the wrong kit...you can replace the Carb 10 times and it will still do THE SAME IDENTICAL THING THE PO HAD!
NO ADVANCE OF THE IGNITION...NO POWER WHEN YOU TRY TO ACCELERATE...If you have the instructions and specs for that kit, it will help you. A distributor that has a small round canister mounted on the outside is a vacuum advance one...and the one with Non-vaccuum will not have that canister. THE KITS YOU CAN BUY ARE NOT INTERCHANGEABLE...IT IS ONE OR THE OTHER.

CHECK TO SEE EXACTLY WHAT IS IN THERE BEFORE YOU SPEND A BUNCH FOR A CARB?

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

Getting in touch with IG mfg... thanks

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

Interesting... upon research IG installed is for CW 12V Neg, my engine label says CCW...

 

[Jacalore]

Re: 1985 MerCruiser 140 Stalls While Accelerating

Re: 1985 MerCruiser 140 Stalls While Accelerating

Disregard, Mfg says right module installed. Gave me a few tests to perform. Will get back...

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

May have solved this problem, need to get out on the water for trial... ignition issue. Cautiously optimistic
Thanks all for the advice and feedback!

 

[Thunderchicken68]

Re: MerCruiser 140 Stalls While Accelerating

Everything here says Carb. Almost guarantee it. possibly accelerator pump, or power valve or maybe just dirty jets. First though, if possible, start from scratch on the current one. Warm engine, I assume the carb is a mercarb with one idle screw. turn that screw all the way in, snug, but never overtighten it. Be GENTLE and count the turns so you can reproduce what you have now. then take it all the way out and look for anything other than a nice straight, sharp point. Screw it back in all the way and back it out one full turn and try to start it.this may take a bit, but it will never be right until it is adjusted correctly. The object is to get it to run, then get it warm, then get it to idle close to the correct speed. probably 550-750RPM. once that speed is close, you can adjust the idle screw in and out, to find the sweet spot. you my have to start at 1100 RPM and work your way there, but I have seen new carb that worked like crap until the idle was set. Many would-be techs will set the idle at 1000 to compensate for a junk carb that cant be made to idle. You probably need to rebuild your carb, but these things will need done anyway. Stop looking elsewhere until you have eliminated the carb. Mikes* Welcome to Mike's Carburetor Parts - Your Number 1 Carburetor Parts Store *has kits and how to videos* MerCarb Marine Carburetor Rebuild - Part 1 - YouTube *that make it easy and cheap. $40 for the kit. $20 for the soak solution at Walmart, some little brushes, and 4-5 hours for your first one. 2 hours after you get a little better. I'm no expert, but if you decide to rebuild it yourself, I would be glad to give you some pointers.


Edit: after I posted this, the rest of the thread came through about the possible ignition issue. I hope that fixed it. ...but I still smell a Carburetor issue

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

Thanks for the info, TC. I ordered a rebuilt carb a few days ago from an exchange. In the meantime, I discovered what may have been the problem all along (an electronic ignition conversion issue). But, I won't be sure until I get it into the water. I'm cautiously optimistic. Of course, I'll have a clean carb next week to fall back on also...

 

[natureschild88]

Re: MerCruiser 140 Stalls While Accelerating

I had the same issue your going through with a boat I recently purchased. Replaced the fuel pump, went through a ton of trouble shooting with the ignition, only thing left was checking the carb. My engine would idle and would die when I tried to rev over 1000 rpm.

I had a 2 barrel on a 4.3 Merc v6, probably similar to your carb unless you have a quadrajet. I removed the top half of the carb and left the lower part on the engine. When I opened it, I discovered the float and accelerator pump were already replaced, they looked new! I removed the jets and half of the ports were clogged shut. I boiled the jets on my stove, using half water half vinegar. Boiled for about 5 minutes, pulled it out, and spayed all of the ports with aerosol carb cleaner. Engine runs like new now.

Hope everything works out for you.

 

[Thunderchicken68]

Re: MerCruiser 140 Stalls While Accelerating

Thanks for the info, TC. I ordered a rebuilt carb a few days ago from an exchange. In the meantime, I discovered what may have been the problem all along (an electronic ignition conversion issue). But, I won't be sure until I get it into the water. I'm cautiously optimistic. Of course, I'll have a clean carb next week to fall back on also...

Keep us posted. Hopefully you have found it. On a side note, what are you doing with the old carb? trading it in? If so, I'm curious as to what they give for them. I am looking to pick up a couple of spares to rebuild for friends of mine.

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

They charge a $25 deposit on core return, much like a battery. Send back old carb, they pay shipping, get your deposit back.

 

[Thunderchicken68]

Re: MerCruiser 140 Stalls While Accelerating

roger that.
best deal that I am finding is $40 for a rebuild-able core. I guess that it is a shame we don't live closer.

 

[Jacalore]

Re: MerCruiser 140 Stalls While Accelerating

To close out this thread, the problem was an incorrectly wired electronic ignition. Added one single wire, as it turned out this was a 50? fix! Took it out today, aside from a few hesitations and an idle stall (adjusted mix, better now), the boat accelerated up onto a plane, and WOT @ 4200 rpm, which is spec. Expect smoother operation with new coil arriving tomorrow. Thanks to everyone and all your advice and comments. I've become quite intimate with my MerC 140!