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Author Topic: Merc 1000SS Stalling In Gear  (Read 5635 times)
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AaronJ
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« on: August 10, 2016, 07:10:33 PM »

OK gang,
Are you sitting down?...
... I finally took the Glastron out yesterday!!!  Grin

I had to go to Morwell for a meeting so thought I'd hit Hazelwood Pondage for a test run.

I had the 1968/69 Merc 1000SS running pretty good on muffs (I've never run her in water).  Idles OK. Goes in and out fo forward/reverse OK.  SO I thought we were ready to go.

I launched and fired her up. 

First thing I noticed was she was finding it harder to maintain idle RPMs.  I wondered if it was due to the back pressure on the exhaust caused by now being in water (and sitting low as she's a big motor for the boat).

To fix that I just upped the choke leaver a little.  But then, when I put her in gear, its like she just choked out.  Could not even hold idle.

Again I assumed it was the extra back pressure with the prop now trying to spin.

I then upped the idle adjusting screw, in stages, but ending up near 1500RPM in neutral... but she choked out just the same once in gear.

I even tried moving quickly from in gear to full throttle and the same choking.

So I bailed and left knowing I'd have to seek your help.

Any ideas what the heck is going on?

AJ

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andrewallan
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« Reply #1 on: August 10, 2016, 08:54:10 PM »

Erk. But well  done for getting out there. I had that issue with my old Evinrude a few years ago, and chucked it on the forum, and it was put down to bad fuel. When I had the problem, motor started OK, idled OK, but just fizzled when put under load  in gear. Happened recurrently, and was somewhat embarrassing, as we were out in the channel in PPB. Managed to putter back to St Kilda at low revs, and that was it for the day. It just felt like something was blocking fuel entry to the engine (intuitive thought, of no rational basis). Subsequent to that, I have always burned off the fuel in the engine after use, by running it out with fuel hose detached, and only ever used premium grade new fuel, and never had the problem again. Just my experience. A bit of a bummer dragging her over to Hazelwood to have that. Did you catch any of the apparently newly released barramundi?

A
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MERCMAN
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« Reply #2 on: August 11, 2016, 08:32:40 AM »

Hi Aaron,
It's great to see you progressing again. This minor problem may take a little time to trouble shoot via the Board. I reckon Mark or I could have her running real good in no time, if we were there with our tools.

The first thing is: The little lever on the side of the control box is not a choke mechanism, it's a "warm up" lever. All it does is raise the RPM's whilst still in Neutral. The choke button is on the top of the control box and it's to only used whilst cranking the motor during each "cold" start. Generally, all Mercs are outstanding when it comes to cold starts. It usually only take a few revolutions of the flywheel and they are purring beautifully. (provided you do it correctly)

Before you do anything, return the the idle screw back to where you found it. I bet you 100 clams the idle screw is not the culprit here. Usually, the idle screw never needs adjustment unless something else is out of whack (that's a special technical term).

I seem to recall you have done a compression test on this girl and I also seem to recall you cleaned the carbies previously? Just to be sure all the innards of the carbies are still working as they should, I suggest you prime the motor with the bulb located on the fuel line, then place a small container and rag beneath each carbie and then undo the "bowl drain screw" to make sure each carbie dribbles out roughly the same amount of fuel. Whilst these screws are still out, squeeze the primer bulb and make sure a good stream of juice flows out from each carbie bowl drain hole. Replace all three screws and report your findings, and the compression results if you have any.

Once that has been done, check that each spark plug is showing signs of uniform burn, be very careful not to mix them up and replace each plug back in the same hole they came out of. This process could assist with future diagnosis. Replace all plugs and be sure to report your observations to The Board before moving on to the next step below.

Each Cabie has it's own "low speed idle jet". This jet is adjusted by turning a slotted screw head, which is located on the top of each carbie. Before you turn it, with a slot screw driver, mark/scribe where the slot of the screw is now in relation to the side of the carbie casting. Once this has been done, whilst carefully counting each HALF revolution, slowly turn the screw clockwise until the screw "seats" gently. Now, straight after turning each screw, write down how far each screw turned for that carbie. Your results may look some thing like this:

Top carbie - 1 and a half turns.
Centre carbie - 1 and a quarter turns.
Bottom carbie - 1 and a three quarter turns.

For a good "factory setting" position for these three screws, I always set them at 1 and a half turns OUT from "seated". From this point, you can set the idle speed with other adjustments elsewhere (another subject) and only then, whilst the motor is still running from your idle speed adjustment process, fine tune each carbie individually until the motor has a nice strong idle and won't die in the bum when it's kicked into gear. Naturally, this process is best done whilst you boat has been launched, NOT on the trailer.

Let us know how you get on with the first step, old mate.

MERCMAN.



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AaronJ
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« Reply #3 on: August 11, 2016, 08:51:45 AM »

Hey Andrew,
Long time!
No Barras.   They have not opened them up to fishing yet.  Watch everyone swarm in when they do.  I reckon they'll last about a week!!!!

Funny though... there were two boats on the day (incl mine), both old, both first time on the water since some new owner work and both dead in the water.  The other guy had a mid 80's Mariner 60hp that was not pumping water and overheated.  I found the wasp nest in the pee hole, but we worked out it was his water pump that was the issue.  We had a good laugh at ourselves and our crappy boats and were thankfully no new shiny boats were around ;-)

I omitted the rest of the 'dramerous' first wetting day...
... as I was passing the Newbrough off-ramp when the drivers side trailer tyre shat itself in spectacular fashion.  Rubber and smoke everywhere by the time I pulled up.
And of course, guess where my spare was?.... in Capricious, as she was the last boat I moved.  Knuckle-head!!!
Pulled the tire off, emptied all gear out of the boat, left it on its belly on the side of the off-ranp, flew to the only tire place I could find with 145/R10 mini rim tyres (other side of Morwell), back to install, drive boat/trailer back to tyre place and get them to replace the other tyre (also about to go I suspected).
So I missed my meeting after all that, and the boat never ran, and I had a head-cold from hell and should have just stayed home in bed.
Oh.... and I need to replace the whole bung fitting on the boat as it leaked water despite being snug.
But at least she got wet , the bilge pump works a treat and I drowned my sorrows with some nice dimsims on the way home ;-)

Hey Guy,
Thanks heaps for the reply.
I was almost going to call you when I was out there, but I knew I was not tooled up enough to do anything in situ.
I'll go through you brilliant list of tests this weekend and report back.

AJ
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AaronJ
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« Reply #4 on: August 11, 2016, 08:55:41 AM »

Forgot to add this...

... at least she looked good in the water!



* IMG_5152.jpg (530.88 KB, 3264x2448 - viewed 125 times.)
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MERCMAN
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« Reply #5 on: August 11, 2016, 09:03:55 AM »

She does look good in the water.

It's a damn shame some other goose had to be at the ramp on the same day to witness your misfortune.
How embarrassing for you. Never mind.... At least the OMC guys are more use to the same feeling. (sorry, I couldn't help myself)

Now watch my very good friend Oldenrude go for the jugular!


MERCMAN.
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AaronJ
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« Reply #6 on: August 11, 2016, 09:24:20 AM »

Na was all good Guy.  He never got far either, before overheating with a stuffed water pump.
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AaronJ
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« Reply #7 on: August 11, 2016, 04:10:26 PM »

Two things before I get to the weekend and start going through your list Guy:

1. She does not have the spec "surface gap" spark plugs (NGK BHUW).  They are the normal type that you set the gap.
2. Last compression test was when Ken (Eltham Marine) looked at it.  He got 140, 135, 130, 108, 97, 125 (cylinder 1-6 and I think he said it was a dry test).  We knew cylinders 4 and 5 were concerning, but I reckon the plugs are not seating well and was going to try and find a spark plug reseating tool to clean up the surface???  I have also been waiting for a chance to get her in the water and let her rip for a while under high RMP and load, hoping that might just het her cleaned out and running a bit better (hence the Hazelwood trip!!!).

AJ
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MERCMAN
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« Reply #8 on: August 11, 2016, 05:12:59 PM »

AJ,
1. The current plugs wouldn't effect the idle that much. Certainly plan to obtain the correct plugs for the future. I get mine from ebay.. a mob in the UK. Big savings compared to local purchase.

2. Pot 5 is a bit of a worry. It may even be a stuck ring? (no funny jokes here thanks). Here is hoping a good clean of the plug seat will arrest most of the leakage. New plugs will always be have new washers which have never been compressed. For that reason, new plugs will always seal better compared to old plugs which have been removed and reinserted numerous times.

3. High speed running won't usually fix frozen needles and seats and blocked jets etc. Ya just can't beat disassembly and detailed/clinical reassembly.

I'm happy for you to call me whilst you are trouble shooting this weekend.

MERCMAN.
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AaronJ
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« Reply #9 on: August 11, 2016, 06:18:42 PM »

Thanks Guy.

New plugs about to be ordered (circa AU$ each is about the best I can find landed out of UK).

I'll call if I get stuck going through your checklist.

AJ
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andrewallan
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« Reply #10 on: August 11, 2016, 10:03:27 PM »

I know I've got an Evinrude, and not a Merc, but I can get my sparkplugs from Repco for about $3 each...

And they also work in my lawn mower ( as does all the old fuel!)...in fact everything works in a lawnmower, doesn't it?!

A
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oldenrude
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« Reply #11 on: August 12, 2016, 08:17:30 AM »

I had a 3cyl 70 horse merc 1979 model years ago that had very similar issues.
 It would run ok IF you could get it into gear and off idle by using the cold running lever. Tried carb rebuilding, crankshaft seals etc.with no result.
 It seemed to run ok for a few hours on brand new buhw plugs but not on old plugs or buhw2 plugs.
This was the clue to eventually solving the problem.
The spark appeared to be visually strong and blue but it was clearly a spark related problem because plugs with higher resistance caused it to play up.
I tried coils & a cdi unit with no result.
Eventually pulled the flywheel to look at the stator. inside the stator is the trigger for the cdi. All of the resin had melted & flowed out of the trigger.
I replaced it with a good second hand and the motor ran perfectly after that.
However several months later the water jacket to the bottom cylinder coroded though so I replaced it with  70hp OMC.
Never had any trouble since and I dont expect any.

Michael
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AaronJ
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« Reply #12 on: August 12, 2016, 09:29:43 AM »

A,
I ended up getting the BUHW off Ebay.au for $8 each.  It was about the best I could find in AU.  SuperCheap had them for more than double that!

Hey Michael,
No matter how much time and money I spend on this old Merc, in the back of my mind, I fear it'll end up being the same scenario.  Do all this work to get it running, but then it has a major parts failure that makes it only good for parts anyway.  But hey.... that's the fun of it I guess ;-)

AJ
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AaronJ
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« Reply #13 on: August 12, 2016, 09:34:00 AM »

Oh shite... I just remembered something Ken Firth pointed out...

... the 'coil to distributor' lead is not an original copper core lead.  Its a newer silicone lead.  I think Ken said something about these newer leads had more (?) resistance?

Could that be a potential contributing factor???

AJ
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MERCMAN
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« Reply #14 on: August 12, 2016, 09:43:45 AM »

AJ,
In my humble opinion... yes it may. I'm guessing Ken Firth will certainly know more than me on the Resistance question as would Oldenrude. He works with Resistance almost every day. (no pun intended)

Do one simple thing for me. Remove each spark plug (being careful not to mix up which one, from which hole) and make sure the business ends of the plugs all have the identical residue on them. More importantly, you are looking for very small water droplets.

MERCMAN.

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