40 Horse Mercury problem

[MuleSkinner]

I have a 40 horse 1983 2 cylinder Merc. Has run great for 10 years. Used it 4 times a week for the last 5 years. Last fall, I put Seafoam in it. It started to run poorly. But also, at the same time, I did not know that the shifter/sparg plug advance screw was coming loose. Finally the linkage came off. (Still ran). I took it to a local shop. The guy hooked up the linkage for $5, without running the engine.

Problem is, still ran bad. Won't idle in neutral without giving it throttle. Also, sounds like it is firing OK, but will often "bog down" at faster speeds. Will pick up again if I change speeds, but will again bog down.

I can't get it into the shop b4 Bigstone trip Friday. I have time to putz with it today and tomorrow. The shop guy suggested blowing out the carb. To me, this looks like a daunting task. I started thinking maybe problem is in the spark plug advance linkage? Is there mechanical adjustments on this? I have never adjusted the idle screw. But since problem also is in high speed, I thought that is not the crucial problem.

I can repack my bearings ok, but I don't have much experience on small engines. Anyone familiar with this engine? Suggestions?

[Valv]

It could be the linkage and actually the adjustemnt screw, if you know where it was (approximately) before re-assembly it might help.

Carbs are my next choice too, just a little gummed and it will run like dump.

Better clean them up before something else goes bad, running motor on 1 cylinder is not very healthy for it.

It's a 2 hour job or few bucks at dealer now, or many hundreds $$ later and the reminder of "I told you so..." for many years

[marine_man]

As far as getting it in.. you could try a crystal pierz marine and use their "urgent care" services to get them to look at it right away...

marine_man

[MuleSkinner]

Thanks Valv. I got a manual from the library. Unfortunately, the thick Merc manual was checked out. So I got about 5 pages only of Merc. And, the part on the advance has the first paragraphs torn out. Which mentions a starting point. Just my luck. but it was not the adjustable screw on the advance that came loose, but rather the bolt holding the shifter and advance arm in place. I only wonder if this might be part of the problem, cuz it ran poorly as the linkage came loose, but continued to run till the bolt came out. And now still runs just the same poorly.

I really am reluctant to tear off the carb. And I don't have a pressure tank to spray with. And I don't have a water tank. Is it of any use to spray carb cleaner into the carb? Visual inspection, the carb looks not that bad. Just black. Or is there more harm than good spraying carb cleaner into the carb without taking it off and apart? Since the problem also started when I put SeaFoam in the gas, that is why the repair guy said maybe a piece of carbon came loose in the carb... I had looked at the filters in both tanks. Clean as a whistle. So I did not take the fuel filter on the engine apart. The engine sounds like it wants to run. Starts easy, but have to give it lots of throttle (So then I have a hard time shifting cuz it wants to kill in the slow neutral position).

I fished too late last year into ice, and the repair guy had put his tank away for the winter. And I kinda forgot about this engine problem over the winter. And started dating a woman, so forgot about panfishing. So just got my boat out of storage yesterday. Poor planning on my part. But lots of people depending on me to also bring my boat to Bigstone...

I'll look at the shifter linkage first. But even that is a two person job. But I do have enough beer to begin...

[MuleSkinner]

Thanks marine man. Just did that. They can look at it tomorrow, but said they cannot touch the carb by Friday, takes too long for parts, etc. They said they don't carry parts in stock for this old of an engine.