problem with 1996 mercury

[mtorts]

Hello everyone, i just bought my first boat with a 1996 mercury 115hp 2stroke 4 cylinder oil injected engine. The problem is that the boat will only start when it is in full choke and i have to allow the motor to run before trying to put it in drive even when the motor is already warm. If i try to put it in drive it will stall (when warm). I noticed that the fuel sqeeze bulb was not full and after pumping several times it did not get very hard. About 10mins later the bulb was empty again and does not seem to be sucking up fuel to the engine. When the boat is running at half throttle it seems to be struggling and the speedometer says it tops out at 26mph which seems slow for this motor on a 19ft aluminum. Do you think all this could be just a matter of changing the fuel line and bulb or something major??: :facepalm: compression is excellent. Could it also be a fuel filter needs to be changed?

 

[Silvertip]

Re: problem with 1996 mercury

The primer bulb does not stay firm once the engine is running because fuel is sucked through it, not forced through it. Before you start throwing parts at it, pull the plugs and see what they look like. Make sure spark is present on all cylinders and that compression is up to spec. Since you just bought the boat you have no idea when the last tune up was done and when the carbs were last cleaned. Stalling is almost always a carburetion issue. You don't have a choke so "full choke" is an incorrect statement. Your engine has an enrichment system that is activated when you push in the key when cranking the engine. The lever on top of the engine is the fast idle lever. It has nothing to do with choking the engine.

 

[mtorts]

Re: problem with 1996 mercury

your right it was the lever that always has to be up in order for it to start as well as pushing in the key. The bulb is soft all the time no matter if im driving or not. Im gunna buy a good carb cleaner to spray in and see what happens. I just changed the plugs so depending on what they look like now should give me a good idea.

 

[wolverine9827]

Re: problem with 1996 mercury

your right it was the lever that always has to be up in order for it to start as well as pushing in the key. The bulb is soft all the time no matter if im driving or not. Im gunna buy a good carb cleaner to spray in and see what happens. I just changed the plugs so depending on what they look like now should give me a good idea.

Hi mtorts,

I'm hoping you got your problem sorted out...

I'm also having an issue with my 96 Mercury/Force 75HP 3 cyl 2 stroke..... it starts fine and idles fine, and seems to throttle up ok while hooked up to the water intake and in neutral (though it sounds a little rough)... the problem is when I'm out in the water.. if I throttle it up too much, it starts to sound weird (can feel vibrations and it sounds almost like it's misfiring) and then stalls... I can puttz around all day with no problem... I have replaced the spark plugs and wires and remixed a new fuel batch with sta-bil - same thing... being a complete newb with engines and that sort of thing, I'm hoping for some direction from others that know more (which is pretty much everyone!)

I don't have a fuel/water separator - should I get one? Where is this usually installed?
How do you clean the carburetors?
How often should the fuel filter be replaced?

Any other ideas? I'd love to get my pontoon back out on the water and be able to get somewhere in a reasonable amount of time.... Thanks for any help....

 

[mtorts]

Re: problem with 1996 mercury

Im also new to outboard motors but it sounds like your fuel filter may need to be changed. You can also buy a can of carb cleaner and see if that helps

 

[1nebel0]

Re: problem with 1996 mercury

Carb cleaner is a waste of money...you need to take the carbs down replace the few gaskets and clean the bowls and blow out the jets...Secondly every boat should have a water separator before the motor...Ethanol plays hell with the fuel system...google it....rebuild the fuel pump every couple of years as the kit is cheap and the diaphrams don't last like they used to. The 115 is a strange animal as it has 4 carbs but only idles on two and has an accelerator pump to help transition to the other two carbs..They are know to idle lousy..still a good motor but just has quirks...

 

[wolverine9827]

Re: problem with 1996 mercury

Im also new to outboard motors but it sounds like your fuel filter may need to be changed. You can also buy a can of carb cleaner and see if that helps

Thanks for the info, I'll get that fuel filter replaced.....

 

[wolverine9827]

Re: problem with 1996 mercury

Carb cleaner is a waste of money...you need to take the carbs down replace the few gaskets and clean the bowls and blow out the jets...Secondly every boat should have a water separator before the motor...Ethanol plays hell with the fuel system...google it....rebuild the fuel pump every couple of years as the kit is cheap and the diaphrams don't last like they used to. The 115 is a strange animal as it has 4 carbs but only idles on two and has an accelerator pump to help transition to the other two carbs..They are know to idle lousy..still a good motor but just has quirks...

Thanks for the info.... I found a fuel/water separator filter to put on... just need to figure out a good place to mount it where it's both out of sight but also easy to get to in order to change the canister when needed - and still have good fuel flow... not an easy thing on my pontoon where the back left compartment is the 24 gal fuel tank. What size would you recommend? I've seen them from 18 to 56 microns and was thinking of going with a 24 or 28 - filter what's needed without restricting fuel flow and choke off my motor...

I'll try to find both the fuel pump rebuild kit and a carb gasket/rebuild kit.... as well as any and all documentation I can find on how to do them both.... to me that's a huge project since I've never done anything like either of those before... replacing the starter, plugs, and plug wires was challenging enough.... Any pointers for doing any of these? I've never done anything like this before and feel like I'm prepping to perform brain surgery where my actions could kill.... I'm afraid to mess it up but can't afford for anyone else to do it...

So for the weekend I have to:
1) Change the Fuel Filter
2) Install a Fuel/water separator
3) Rebuild the fuel pump
4) Tear down, clean, and regasket the carburetors

wow. color me afraid... very afraid