Motor cut out and then died

[superdave1984]

Last time I took the boat out it was running like a champ. We got about a mile and a half from the boat ramp when it cut out and then died. Went to restart and when pulling the rope it only came out about a foot and it stopped hard. Tried again and the rope snapped. Got towed back.
New rope installed and it still only pulls out about a foot. Pulled the spark plugs and they don't look terrible. Motor spins over fine without the plugs. So what is the likely problem? This is an early to mid 90's 25 hp Mercury 2 stroke.

[gunwhatgun]

Please forgive me but I always ask these questions, I know you probably checked these things but...... When you went to restart it did you make sure it was in neutral? if you did while on the water, did you double check on land by turning the prop? Without the plugs in, they are easy enough to spin even in gear. A rope coming out a foot and stopping hard indicates to me that you have a mechanical neutral interlock that was engaged to prevent you from starting it in gear.

As to the cutting out and dying, again I am sorry for the simple questions but.......Did you run out of fuel? Did you check to make sure you did not drop a plug wire or pull the overboard switch??

I have had so many people bring me engines that were "locked up" or "seized" that were either just in gear, or had a failed neutral safety, some simple issue with the lower.

The same for the sudden dying, If the engine did not seize, and you said it spins over, then you lost spark or fuel.

[superdave1984]

Please forgive me but I always ask these questions, I know you probably checked these things but...... When you went to restart it did you make sure it was in neutral? if you did while on the water, did you double check on land by turning the prop? Without the plugs in, they are easy enough to spin even in gear. A rope coming out a foot and stopping hard indicates to me that you have a mechanical neutral interlock that was engaged to prevent you from starting it in gear.

As to the cutting out and dying, again I am sorry for the simple questions but.......Did you run out of fuel? Did you check to make sure you did not drop a plug wire or pull the overboard switch??

I have had so many people bring me engines that were "locked up" or "seized" that were either just in gear, or had a failed neutral safety, some simple issue with the lower.

The same for the sudden dying, If the engine did not seize, and you said it spins over, then you lost spark or fuel.

Thanks for the reply. It was in neutral. However there is a good bit of slop in the throttle handle so it is possible something has gone haywire with that. I am not 100% certain the neutral lockout even works on this thing as there have been times I did not have it in neutral and it started anyway and immediately moved the boat forward.
It is not out of fuel, that was my first thought. It has a half tank of fuel. Plug wires are on tight. This old thing does not have an overboard kill switch, which is dumb on my part.

I don't have any experience with these things, only on automotive engines. On a car I would think I have stuck exhaust valves causing it to buikd up too much pressure but I honestly don't know how these little things work on the inside.

[DockShootinJack]

If it is 2 stroke it will have no valves. At least not like a car engine

[gunwhatgun]

OK, all of that is good info, and DSJ has told you correctly, 2 strokes do not have lifter type valves, they have read valves. Usually when read valves go bad they fail to seal properly, and you have a low compression situation, this would not stop you from being able to pull the rope. You have proven that the neutral safety is in-op, so that wasn't the problem. If it has just died and wouldn't start back, my guess would be you lost spark on one or both cylinders or you sucked some trash into the carb. The fact that it wouldn't pull after it died is more concerning, because that suggests an over heat situation. You said it pulled with the plugs out though, have you tried again to pull it with the plugs back in? IF it will pull now, being cool, you over heated. Could be the impeller, which is the usual suspect, could be incorrect oil\fuel ratio, which can happen when oil pumps go bad on auto mix models. I am not sure if yours is.

[MDCrappie]

You have proven that the neutral safety is in-op, so that wasn't the problem.

I would look at it differently. He has proven not that it is in-op, but that it is not functioning correctly. If it is a mechanical stop, and is maladjusted it could malfunction by starting in forward, and also malfunction by not starting in neutral.
Need to remove the cover and watch the recoil starter as you pull it slowly.

To the OP - you say "the motor spins over fine without the plugs" - is this by pulling the rope? or spinning the flywheel by hand?

[scout-j-m]

I'd pop the recoil start assembly off and try to turn it over by wrapping a rope around the flywheel. If it does turn freely by hand then this should work and if it does will tell you its a lockout feature malfunction on the recoil starter.

I have a 94 model Mercury 25....its remote model but should have the same lockout. On mine, it's that spring loaded pawl on the starter as seen in the pic.

[superdave1984]

I would look at it differently. He has proven not that it is in-op, but that it is not functioning correctly. If it is a mechanical stop, and is maladjusted it could malfunction by starting in forward, and also malfunction by not starting in neutral.
Need to remove the cover and watch the recoil starter as you pull it slowly.

To the OP - you say "the motor spins over fine without the plugs" - is this by pulling the rope? or spinning the flywheel by hand?

That would be using the rope. Raining today so I am not going to mess with it. Overheating does not seem to be an issue, at least I don't think. I put a new water pump impeller on before winter storage and was getting a good stream out the pee hole when I fired it this summer and I look at that every time I put it in the water.

[gunwhatgun]

So let me see if I'm on the right page. The pull rope is repaired, you can pull the engine over with the rope, IF the plugs are out, with the plugs back in, the engine will not pull...

Have I got it?

[MDCrappie]

That would be using the rope. Raining today so I am not going to mess with it. Overheating does not seem to be an issue, at least I don't think. I put a new water pump impeller on before winter storage and was getting a good stream out the pee hole when I fired it this summer and I look at that every time I put it in the water.

OK, only issue that would cause that would be a reed valve stuck closed. Not sure how that can happen though. I'd try it with each of the plugs individually. See if it will pull with either in, but not both.