Problems with Merc 50 4 stroke

I have a ’98 Mercury 50 horse 4 stroke on a 16′ boat I bought a few years ago. For the most part the motor works fine, however, out of the blue it doesn’t want to start. It takes some playing with the fast idle and about 25 cranks and it eventually starts. Also, sometimes after it starts and I put her in forward gear it coughs and spits and grunts and coughs and finally gets going. I’m guessing it’s not getting fuel??? but what could cause something like that??? I’ve lived with this problem for a few years now but seeing the info exchange on this site I’m thinkin’ somebody might know what’s up with this thing. Any ideas would be appreciated.

Is this a Mercury motor or a Mercury Force?

Motor.

Could be bad gas or water in the gas? Sounds more like fouled plugs and bad gas.???

Also remember 4 strokes are cold blooded in cold weather.

Try some seafoam in the gas tank, I usally have similair problems in the spring with my runabout, I always put it in the first take of gas, it gets rid of the water, it may run a little ruff on the first tank, but the second tank you will be nicely surprised. you can get it at about any auto or marine supply shop.

Good luck
MiniGrub

I put in new plugs last summer and have tried “heat” to get rid of water but neither seemed to help. This happens in cold and hot weather. Do these things have fuel filters or fuel pumps? I’m not the greatest mechanic by any stretch but I am willing to try just about any suggetions that come up. I am a little leary about taking it to the shop because I had an old truck that would stall for no apparent reason and put about $800 into until I finally traded it in for something else. Is that my next option? I’d like to try a couple things before that happens as I am stretched kinda thin these days. Thanks for the input!

try squirting some mixed fresh gas in while cranking it and you will quickly learn if it’s getting fuel. I don’t think “heat” is a fuel stabilizer. does the gas smell old? It’s getting warmer too, that might solve the problem on it’s own.

Find and clean the fuel filter. Is the motor carbed or fuel injected?

newt, does it have a choke or primer button? Sometimes the primer hose going to the carb will work loose or come off completely. I’m not talking about the “primer bulb” here that you squeeze.

I had similar problems with my 2001 4 stroke Merc. Check to see if there is a yellow ring on the pump up ball. If there is you should only pump the ball enough to just getting the gas in the motor. If you pump the ball hard you are flooding your engine. I believe you have carburation like I do on my 90. I have not had a problem since I started not pumping the ball hard. I was first told of this by a hellicoptor pilot and when I raised this up to my dealer he called Merc, went out and looked to see if I had a yellow ring, and then told me what Merc said. I called Merc and let them know that they should have that info in the manual. I was up to Winnie on two different trips and could not get the motor started. I took it into Grand Rapids Marine and they thought I had bad gas also. I do use Sea Foam year around as that is what they recommended. I also use non ethanonal gas with 91 octane rating. I use this in all my small motors also. Try the ball pump information before you spend any more money at the repair shop.

It’s carbed. I don’t think it has the yellow ring on the ball (it’s in storage up north so I can’t confirm that for about a week). I’ll use the sea foam to see if that helps and will clean the fuel filter and see if that does the trick. any other suggestions?

Dump the gas out of the tank. Rinse tank with a small amount of gas. look into tank make sure it is clean. Start with fresh gas. If still does not start easily pull plugs and clean or replace. Todays gas goes unstable in a very short period of time. If you are not going to use it up in a couple of weeks you should add a fuel stabilizer such as stable. Stable in the gas also prevents your fuel system from varnish which can clog your jets in the carb. This varnish comes from the gas when it sits in your carb. too long. Stable will prevent this from happening. I add it to every tankfull cause it mey be a couple weeks or more till the next fishing trip. Give it a try it may solve your trouble. I have used stable for the past 10 years and have had no trouble with starting. You still may need to get your carbs cleaned by a service man. Good luck.