40 hp merc info needed

airshot

Rear Admiral
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Jul 22, 2008
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I recently purchased a 1982 40 hp merc, it ran like a top. Mounted it on my boat, it would not open up, found the problem with cable adjustment. Took it back out today, let it warm up, idled out and punched the throttle, it took off great, then a vibration started, we cut back on the throttle and the motor diedout, restarted it easily, but now the motor won't go faster than fast idle. When you try to accelerate it dies out. Checked fuel system, all appears OK, thinking ignition mabey?? We idled back to the dock and when going into neutral the motor started increasing in speed to the point we had to shut it off. The throttle stop in the motor is back against the stop, we restarted it and it started running very fast again, it restarts easily..
Linkage appears fine and working properly, anyone with experience with something of this nature ? Unless I hear of a simple fix, it may be off to the repair shop, which will probably end my boating season early. Thanks in advance for all of your help.

Airshot
 

Kirscher

Cadet
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Aug 30, 2008
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Re: 40 hp merc info needed

I had a situation where the symptons were identical to what you have. My problem turned out to be a magnet in the head came loose and reattached in the wrong place, causing a partial out of time condition. At idle and low speeds the engine worked fine. On open throttle, it would die out but always restarted.
 

kellyisu

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Oct 3, 2007
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airshot

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Re: 40 hp merc info needed

Thanks for all the replys, I did forget to mention that the lower pivot mount on this motor is loose, became more loose after greasing it. Has anyone had experience with these, causing high speed vibration or how to replace what I assume to be a bushing. Have to wait for a manual and getting anxious.
Thanks again.

Airshot
 

kellyisu

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airshot

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Re: 40 hp merc info needed

Kellyisu,
Thanks for the diagram info, the really scary part is the parts are no longer availiable on that web site!! I guess I will have to bite the bullit and find a mechanic in my area. Thanks again

Airshot
 

airshot

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Re: 40 hp merc info needed

Kellyisu,
Thanks for the diagram info, the really scary part is the parts are no longer availiable on that web site!! I guess I will have to bite the bullit and find a mechanic in my area. Thanks again

Airshot
 

kellyisu

Petty Officer 3rd Class
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Messages
75
Re: 40 hp merc info needed

When working on my motor I had a few parts that I could not find anywhere as well, nowhere on the web( i called many places in the united states and a few places referred me to a place called Seaway) and not on ebay.
I was told about the place in Seattle Washington that specialize in hard to find and no longer available new old stock parts for Johnson, Evinrude, Gale, Chrysler, Force, and Mercury outboard motors as well as OMC and Mercruiser sterndrives and engine parts and Chris Craft inboard V8 engines.

They had what I needed!

I am almost certain they will have what you are looking for and it only took a few days to get the parts, and I am located in Iowa.


Seaway Marine Incorporated - (206) 937-7373

Here is their website- http://sea-way.com/

I'd give them a call!!!!! Have the part number Ready when you call.
 

airshot

Rear Admiral
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Jul 22, 2008
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4,219
Re: 40 hp merc info needed

Just a note for any of you that responded or followed along on my merc problem, it was the spark plugs !! I have never had plugs foul out but still run at idle speed before, when I bought the replacements the parts man sold me two different plugs, one is the type without a protruding center electrode as was in it, and the other was a normal looking plug with extended center electrode. It was explained to me that merc had some problems with fouling of the funny looking plugs and the other two were the replacements. Put in the new plugs and it took right off, high speed as well, even idles better. The real test will be getting out on the lake.
Second problem was the vibration, put a new prop on to see if that cures the high vibration problem, I understand a vibration can occur if the prop hits something and spins on the rubber hub.....we will see.
My recomendation to all...make sure you have a spare set of plugs with you!!

Airshot
 

kellyisu

Petty Officer 3rd Class
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Oct 3, 2007
Messages
75
Re: 40 hp merc info needed

Yep- I just started carrying a a spair pair on me. Good to hear you found it was a cheap fix:)
 

mthieme

Captain
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Oct 6, 2007
Messages
3,270
Re: 40 hp merc info needed

I had the same issue earlier this season.
It turned out to be a saturated float.
As for the pivot issue...grab the front and back of the motor and see if you can move it back and forth. If you can, the bottom mounts need replacing.
Been there too.
There are also three top mounts.
 

airshot

Rear Admiral
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Jul 22, 2008
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4,219
Re: 40 hp merc info needed

Yes, the bottom mount has some play in it, it appears to have excess gap in that it has extra space to move up and down. the lower being mounted in rubber has flex that causes this gap to open up. From what I see the L/U must be removed to replace that lower pivot mount as what appears to be the shift rod goes thru there, sounds like fun!!
My question to you that have had this lower mount play, has it caused high speed vibration or shaking? Thanks again to all that responded

Airshot
 
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