'84 Mercury 60HP: Starting & Stalling Issues

[pastorbobnlnh]

As I mentioned in the past, I'm a newbie to boating and really not a mechanic. Your collective help, wisdom and guidance is appreciated! :thumb:

My 1984 60HP 2 cycle 3 cylinder has two issues. First with starting when the engine is hot from being in the sun and the temps are above 80F (not from being hot after running). Second with suddenly stalling after cruising for about 20-30 minutes and it was running fine up to that point.

Starting Issue:

If we take it out first thing in the morning when the temps are below 80F (approximately) and the sun has not been shinning on the engine, it will start right up on the first or second crank. However, if we wait to later in the day and it has sat in the sun for many hours it will often crank until the engine is flooded and won't start at this point.

We have found it helpful to cover the engine with a wet, light colored beach towel ("to keep her bottom cool" as my wife says :facepalm, but this doesn't always work.

Stalling Issue:

This is a new issue which has just surfaced in the past 3-4 outings. After starting and allowing the engine to warm up for a few minutes as we untie and push off from the dock, the engine idles and runs well. We will then usually cruise at around 1500-3000 RPM and the engine runs very nicely. Even if I push the throttle to full, the boat will go up to and run at 5000+ RPM and do fine.

However, after cruising for 20-30 minutes, all of sudden the engine will stall. This usually happens at between 2000-3000 RPM. The engine will start but will stall again as I throttle up to and past 2000 +/- RPM, and stall again. Basically at that point I have to idle back (keep it below 1500 RPM) to the dock and end the cruise. I should mention the engine sounds different at this point as well. Sort of rough but just barely.

Once the engine cools off, it will start and run fine until about 20-30 minutes into the cruise.

Thanks for any tips before I pull it out of the water and head to a mechanic.

 

[pastorbobnlnh]

Still looking for guidance on these issues. Thanks for any suggestions:

I've been trying different possibilities to see if I can solve the stalling problem. I thought that maybe the plastic tank was not properly venting and creating a vapor lock. It is older and has distorted from being over pressurized.

So I switched back to my metal tank last evening. But no luck. I had the same result: 25-30 minutes of great running and then "the stall." No issues re-starting but then it will not throttle above 2000RPM without stalling again. Limped back to the dock and tied up for the evening.

I need a marine mechanic!

 

[DavidMoore]

Had a similar stalling issue once, it's never happened again since I did a fuel pump overhaul, fuel line replacement, and fuel filter replacement. That was 3 years ago.
I suspect it was the fuel pump overhaul that had the most effect, but because all 3 were done at the same time, I'll never be sure.


No ideas on the starting issues though, I would have thought it would start easier when warm. Maybe over fueling? try giving less choke.

 

[pastorbobnlnh]

Thanks DavidMoore. I appreciate the tips.

I just got off the phone with two different mechanics. One said a carburetor rebuild and the other said the Stator is probably bad. Hmmmmm!

I'm going to probably take it to the one who mentioned the Stator.

 

[DavidMoore]

I would put clear plastic tube between the fuel pump and 1st carb. Run engine and see if there are bubbles passing through with the fuel. If there are bubbles there is a leak / blockage in the fuel system. That would need to be fixed and should be cheap to do.
I would also attempt to rebuild the fuel pump and clean the carbs myself being reasonably easy to do + relatively cheap.
Problem still not fixed then I would look at the stator, because that's expensive.

Start cheap and easy, work up to expensive and complicated. But that's just me and I'm tight as a ducks backside , so do what you feel is right.