V200 Merc 2.4 Rough Idle and then dies when put into gear

**bimmer1** · 05-09-2020, 02:19 PM

Hello everyone

I really need a little help from all you S&F folks.
My V200 2.4 Merc is causing me a lot of trouble. It has a rough idle and I have the feeling that it is not firing on all 6 cylinders. However when raising the revs (in neutral of course, on the tab next to the throttle) it clear its throat and goes on all 6 cylinders. When backing of againg it returns to the rough idle. The above is still on the hose but when running in sea water the same happens but when put in gear the motor quickly dies. Trying to apply throttle doesn´t help.
Here are a few facts that might rule out some issues:

Last year motor has two new sleeves installed together with a new piston. All rings were replaced at the same time. I now have 100 psi on all 6 (same as before i blew the one piston two years ago). Some say this is rather low but since all 6 cylinders are giving the same reading I guess it´s all good.
All carbs cleaned and no leaks are detected.
Fuel filter replaced
I see spark on all 6 plugs (Or so I thought. Today 11MAY20 I didn´t see any spark on the entire left bank)
Plugs look all the same (wet and with a bit of black deposit)
After the "rebuild" last year the motor ran just fine afterwards, so I have no reason to believe that the problem has anything to do with the rebuild.

Hope for your help in solving this problem, thanks.

Bimmer1

**KIRCHNER** · 05-09-2020, 03:19 PM

When its on the hose, pull off each spark wire for a second and note the rpm drop. they should have the same response. easy way to find problem cyl. loosen them all slightly first makes test easy. you also can put a short piece of garden hose up to your ear, other end in front of each carb at idle. all sould have pretty much same sound. can locate a bad reed[s]. GL. Also you can find an out -of-sync carb.

**bimmer1** · 05-09-2020, 04:03 PM

Thanks, I´ll try that tomorrow

**rgsauger** · 05-09-2020, 07:42 PM

100 psi sure is low. Have you ever done a good decarbon on it? How long since proper link and sync on carbs and timing? How old are plugs? Fuel?

**Capt.Insane-o** · 05-09-2020, 08:08 PM

I was wondering a short time ago how you were doing with that. That ignition system should jump a 1/2 inch gap easily at cranking speeds. Pull the air box off and give the primer bulb a good squeeze to check for a drippy carb too.

**Merc 2.5** · 05-09-2020, 08:32 PM

I'm with capt. Squeeze bulb make sure it's not puking, also go to autozone, advance auto, orileys, and get a cheap inline spark tester, gonna go out on limb and say switch boxes, 100psi will still run but very close for rebuild

**mrichartz** · 05-09-2020, 08:40 PM

If you have 100osi on all 6 do you have another gauge you can use?
AutoZone lends them out alot of places too.not that they are that great but

**eli** · 05-09-2020, 08:43 PM

Low speed on stator is out

**Merc 2.5** · 05-09-2020, 08:48 PM

Well sure is alot of guessin goin on , just gonna have to take it 1 thing at a time , it will run on 100 psi , now need check fuel , then fire
Switch boxes die more often than stator , alot more often

**Capt.Insane-o** · 05-09-2020, 11:23 PM

He's in Denmark. I sent him over some sleeves and other parts last year I think. Access to a DVA meter would be helpful too.

**bimmer1** · 05-10-2020, 07:16 AM

Hi all
Thanks for all your replies. I'll look into all your advice asap. It might take some time (work, family etc) to try/test it all but I will keep you posted as I progress.
Kind regards ��

**bimmer1** · 05-11-2020, 09:46 AM

Hi
So today I learnt that the entire left bank has no spark. Occasionally left bank fires for a couple of seconds and then dies again.
No dripping from the Carbs though.
What to think of that?
Regards
Bimmer1

**Dave Strong** · 05-11-2020, 10:23 AM

Capt said no DVA meter so swap the 2 switch boxes. If the rt bank now has no spark replace both switch boxes. If still no spark on left side good chance stator is bad.

Dave