1986 Mercury Inline 6 Bogging Help!!!

SpikeJ

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May 26, 2009
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15
Having problems with engine bogging. History ran last weekend like a top, skying pulled skiers up no problem this weekend took it out and when I pushed hard on the throttle it bogged and stalled tried it several times and bogged down most times but a couple times it did accelerated ok, but just ok, but mostly not. Adjusted the idle no change. The primer bulb remained firm. Last note had problems with Fuel guage and looked under the dash found the temp gauge disconnected and bad fuse holder on the fuel gauge connected temp gauge and replaced fuse holder for the fuel gauge. Both seem to be working fine. Could the gauges effect the performance? Current draw or shorting? But why sporadically? Lastly I have disconnected my tilt kill switch, it seems I have a bad switch, waiting until I can get the $50 bucks to replace it. For time being I have the wire out of the switch taped off and I am careful not to tilt engine while running. Any thoughts??
 

SpikeJ

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May 26, 2009
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Re: 1986 Mercury Inline 6 Bogging Help!!!

As an update went out last night some and found what I assumed was the problem advance linkage was disconnected the nut fell off and linkage slipped out of the mounting hole. Reconnected and I am part way their when I did get the boat up and running by some coaxing it ran good could easily max out the RPM's to 6000. Boat speed 50 MPH (16' Checkmate). but still had some hesitation & bogging which required nursing at the 2000 rpm range. I now assume I need to do a link and sync. For my 1986 Inline 6 the Chiltons says to first set the flywheel to TDC and then back to .464. If the boat was running good before the linkage fell apart would the flywheel be off or would this step be necessary? How could it get out? I assume that once the piston and flywheel are set their is nothing that can get out of sync. I see that part of this is to adjust the pointer but again it would seem if the pointer is set and it hasn't been tampered with the first step should be good! Any thoughts? I hesitate to get involved in the first step because it requires a dial gauge which I don't have.
 

Chris1956

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Mar 25, 2004
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28,340
Re: 1986 Mercury Inline 6 Bogging Help!!!

You may use a ruler to set the timing pointer, if you are careful and accurate.

I couldn't tell what part of the throttle linkage fell apart, however, if it was just where the throttle cable attaches, the timing should not have changed.
 

SpikeJ

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May 26, 2009
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Re: 1986 Mercury Inline 6 Bogging Help!!!

I'm not sure what you mean by using a ruler. The first step is to find TDC and the adjust the pointer so thatit is at .464 BTDC the upper housing support has a timing pointer that is bolted down and when you have successfully found the .464 BTDC you set the point by losining two bolts and slide the pointer to match. Then you use a timing light. I assume the pointer has not changed so it sould be ok??????????? It was the spark link #34 and nut #38
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that came disconnected from the lower throttle housing the spark link has a thread that looks down and the nut is threaded from the bottom. While it is an aircraft type nut with a nylon insert it losened up and fell off. It was in the bottom cowling and I put it back on and tightened it up. My guess is though when it was loose it had just the right combination that the engine accelerated fine. The spark link is the linkage between the throttle linkage and the link to the upper carburator.
 

Chris1956

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Mar 25, 2004
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28,340
Re: 1986 Mercury Inline 6 Bogging Help!!!

It looks like the linkage that disconnected is not adjustable. Once it is tightened, it should be in the exact positon it was, before it loosened, right?

So it shouldn't affect the timing.

On setting the pointer. .464 is inches below TDC. If you measure form the plug hole to the top of the piston, accurately at TDC, and add .464 inches, you can then set the piston to that spot, and adjust the timing pointer to point to the spot on the timing decal. I usually use a caliper accurate to .001 Inches, but a ruler can work as well. You may need to convert the decimal to 32nds
 

SpikeJ

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May 26, 2009
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Re: 1986 Mercury Inline 6 Bogging Help!!!

Got it. But should that change after it is set initially? Unless you pull the fly wheel, but otherwise it should remain the same?
 

Chris1956

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Mar 25, 2004
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28,340
Re: 1986 Mercury Inline 6 Bogging Help!!!

In theory the timing pointer should not change position. However, it is real close to a flywheel that is spinning, and linkage that is moving, so who knows if it is in the correct position after that. it is only a piece of wimpy plastic....
 
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