Stalling 1998 90 Hp Merc Force Outboard

[dbmacboat]

Hi there, hoping to get some help. My 90 merc outboard is stalling randomly. It has a portable gas tank c/w primer bulb.

Initially I found the primer bulb had gone a little soft, so if I squeeze it and restart, it runs for a while then stalls, usually on take off but sometimes in mid throttle. Otherwise it seems to run fine. It's very random. I've replaced the primer bulb, and put a diaphragm kit in the fuel pump complete with all the springs. Checked the plugs and cleaned them although they weren't very dirty.

After some problems starting and running after the fuel pump work, it seemed to run fine, but then did the same thing. It does sound a little different at idle though now, it seems to have developed a bit of putt putt sound that's different from the normal sound.

I'm thinking fuel filter now, any other suggestions???

Any help would be much appreciated!Thanks!!!

 

[mikeneal]

Re: Stalling 1998 90 Hp Merc Force Outboard

Filter is great place to start, could also check the fuel line for air bubbles to make sure if is not getting air in the system.

 

[dbmacboat]

Re: Stalling 1998 90 Hp Merc Force Outboard

Thanks Mike! Any thoughts on how to check for air? or just tighten up all clamps on lines fuel related?

 

[Blevins]

Re: Stalling 1998 90 Hp Merc Force Outboard

It's near impossible to check for air leaks. The best thing to do would be to change the fuel filter because the more regularly that is done the better it is for everything. I'm assuming the fuel isn't old and couldn't have water in it? My motor ran at slow just fine, then it would run at wot just fine, but then stall. And it was because water was in the gas.

 

[cookey]

Re: Stalling 1998 90 Hp Merc Force Outboard

i have had simealar problem with my merc 60 i tried every thing but the real problem turned out to b a loose cover on the motor ans sum water was splashing on the plug leads causing them to loose spark ,,
the engine sounded bad when this happens so after fixing the cover and chaining the plug leads she is running sweet ,,
this is just another suggestion as i went down the road of fule causing the problem but it was not fuel ..
this might not b your problem but it worth a look because it only takes one or 2 drops of water to slow her down next time it happens check the plug leads it worked for me

 

[79Merc80]

Re: Stalling 1998 90 Hp Merc Force Outboard

Hello:

I really hate to break this too you, but what you have is a Force, NOT a Mercury. They are not the same engine. Different displacement. The only thing that was the same on the last models were the lower unit and the electronics.

There is a Force/Chrysler forum for your engine

 

[dbmacboat]

Re: Stalling 1998 90 Hp Merc Force Outboard

Oh ok thanks, never thought twice about it because the engine cover says FORCE and then below says BY MERCURY MARINE. So a bit confused now. Can you explain?

 

[dbmacboat]

Re: Stalling 1998 90 Hp Merc Force Outboard

Thanks for all the replies. Replaced fuel filter last night, bought a new tank with different internals. Replaced the plugs, removed the air intake and inspected what I could of the carbs, they all looked really clean. Took the bowls off (except the bottom carb bowl, it's a bugger!) and inspected, they were all clean. Retightened the fuel pump housing screws.

Is there any air intake filter media on these outboards?? And where do the carbs get their air if the housing is so nice and watertight? (a couple of cadet questions, haha)???

What I found was a lot of fine soft debris inside the motor housing, which is usually really clean. Found a little yellow circular peice of plastic on the bottom of the inside of the motor housing. Then checked the inside top of the cover, sure enough, the foam sound attenuating material had fallen down on to the top of the flywheel of the engine. The yellow plastic was from the flywheel nut cover. When the engine was running it must have mashed up that peice of plastic and some foam from the inside of the motor cover and sprayed it all over the inner housing.

Might have gotten some of the debris in the carbs !$#@$^^% argh!! That's why I'm wondering about filter media in the air inlet for the carbs (mine has none).

Well, will test it tonight weather permitting.

Any other thoughts or suggestions are appreciated!

 

[79Merc80]

Re: Stalling 1998 90 Hp Merc Force Outboard

I don't understand why there would be confusion. IT's a Force, so use the Force/Chrysler forum. There isn't one that says Mercury/Mariner/Force. is there? Read the BIG letters on the cowling, that's what you have.

When Brunswick aquired Bayliner, along with it came the Force/Chrysler outboard. Mercury Marine tried to update the line, but then dropped it cause Mercury and Mariner already had engines in the hp ranges that had a better reputation.

"Made By Mercury Marine", doesn't make it a Mercury. That's why a Mercury or a Mariner don't have other names on them