Newbie help - Round 2......please?

[jm999]

1964 Mercury Merc 850

Runs fine on muffs

Heres what my motor is doing in the water:
- I have to have the fast idle way up to start, sometimes even when its warmed up
- always have to choke it regardless
- has a hard time idling in the water, won't go into forward without stalling unless I gun it fast which can't be good for it i assume

Some stupid things I've done:
:facepalm: ran it with old gas that was a little heavy on oil
:facepalm: installed the wrong spark plugs
:facepalm: screwed around a little bit with the idle stop screw (after the above)

what should I do first? Get good gas, proper spark plugs, and give it another try? Or should I cut right to tearing apart the carbs? The carbs look like a real pain in the *** to get off of this motor.

Thanks for any advice.

 

[Jake_MN]

Re: Newbie help - Round 2......please?

It sounds like you have a lean condition. But before you can know that for certain you should get correct sparkplugs, gap them correctly and get fresh gas. If you can reset the idle screw to the original setting do so. If the problem then persists you're probably looking at a carb cleaning. You can mess with the idle jet on the carbs to see if that helps first, and if you're lucky you can try running a gallon of premix with a few ounces of SeaFoam in it to see if you can free up the idle circuit. But be forewarned: the SeaFoam trick will make things worse as often as it will clear anything up. Sometimes it clears the circuit, sometimes it does nothing, sometimes it dislodges a bit of gunk which then gets wedged in your idle circuit and makes the engine un-startable. Best bet is to start with the plugs and gas and post back with results. Good luck.

 

[jm999]

Re: Newbie help - Round 2......please?

Thanks for the advice! Will try what you suggest and let you know how it goes.

 

[jm999]

Re: Newbie help - Round 2......please?

Ok, drained the tank and put fresh gas/oil in, and also put the correct spark plugs in. Its running much better on the water now, but I still have to gun it a bit to go forward without stalling. Once its up to speed it no longer bogs out on me, stays nice and steady and sounds good. Its idling around 1100 rpm which I know is probably a little too high? I also don't need to choke it when its warm, but after about 5 mins I have to choke it again.

Thanks!

 

[Jake_MN]

Re: Newbie help - Round 2......please?

Yep, 1100 is a bit high. Is that in forward gear or in neutral?

You need to choke it after it warms up? Is that at all times or just when idling?

 

[j_martin]

Re: Newbie help - Round 2......please?

Ok, drained the tank and put fresh gas/oil in, and also put the correct spark plugs in. Its running much better on the water now, but I still have to gun it a bit to go forward without stalling. Once its up to speed it no longer bogs out on me, stays nice and steady and sounds good. Its idling around 1100 rpm which I know is probably a little too high? I also don't need to choke it when its warm, but after about 5 mins I have to choke it again.

Thanks!

To verify some of what's been happening. Excess oil in the fuel will cause the engine to run lean. It's a combination of viscosity and available heat content issues.

Of course wrong plugs throw a wrench into the works.

The best thing you could do right now is get the manufacturer's service manual, and follow instructions in it for a linkage and timing adjustment (link-n-sync)

Timing and carburetor throttle valve are progressively synchronized in these big 2 cycle engines. If it's set up right and nothing is wrong (carbs, ignition) the engine will perform well over it's entire operating range.

Almost always, when I see an engine in reasonable condition with performance problems, it's because someone has been "messing with" adjustments without knowing the overall sequence, leaving something out of sync.

hope it helps
john