gas cuts out on 2004 bigfoot mercury 25hp outboard.Changed spark plugs helped but?

[racerone]

Home made tester.----You take 2 pieces of wire.----Glue them on a piece of carboard / plywood with a 3/8" gap between them.-------Attach one end to motor block.----Stick other end in a sparkplug boot.---------See if spark can jump that gap.-------Any wire , even stereo speaker wire will do the job.

 

[Fredfloat]

Home made tester.----You take 2 pieces of wire.----Glue them on a piece of carboard / plywood with a 3/8" gap between them.-------Attach one end to motor block.----Stick other end in a sparkplug boot.---------See if spark can jump that gap.-------Any wire , even stereo speaker wire will do the job.

Thanks for that. Would you mind telling where the best place to attach the wire to the motor block?

 

[racerone]

Basically clip it on or behind any bolt for a good ground.

 

[Fredfloat]

Basically clip it on or behind any bolt for a good ground.

OK. Thanks

 

[dadofemily]

To eliminate a fuel starvation issue, I would have someone help and while it's dying at its high throttle setting, spray some gas in the intake.

I had a bigfoot 50 doing almost the same thing and it was the needle/float being plugged with crud. Sometimes opening sometimes not. but never letting enough gas in for full throttle for any length of time.

 

[Fredfloat]

To eliminate a fuel starvation issue, I would have someone help and while it's dying at its high throttle setting, spray some gas in the intake.

I had a bigfoot 50 doing almost the same thing and it was the needle/float being plugged with crud. Sometimes opening sometimes not. but never letting enough gas in for full throttle for any length of time.

Very interesting. After they did that did it start working again or did it mean you had to replace something? Thanks

 

[Sea Rider]

That motor once started up will keep running no matter if the battery is having discharging issues. Age is age and 14 years are 14 years, worse if has sat in the water in a dock slip according to your post. Moisture will screw any electrical or elctronic part over time. What screws up any motor is not being run from time to time over time and where has been kept for all those years.

Check if someone can lend a Ignition Coil to swap and test while the combo runs on water at speed. If OK buy a new IC and save lots of cash by not taking the motor to nearest dealer. Would hate to pay $100 an hour for electrical testing..

Clean carb, check fuel pump cond if fuel starvation is suspect and make another test run at speed, if with no avail it's an electrical issue. A spark can jump properly when tested at neutral and 0 load, other scenario is jumping properly when the motor is at load say running midle to full throttle grip...

Happy Boating

 

[Fredfloat]

To eliminate a fuel starvation issue, I would have someone help and while it's dying at its high throttle setting, spray some gas in the intake.

I had a bigfoot 50 doing almost the same thing and it was the needle/float being plugged with crud. Sometimes opening sometimes not. but never letting enough gas in for full throttle for any length of time.

Could you say where you sprayed that gas? I took the clip that goes from the bulb off and pushed the rod going into the motor and sprayed carb cleaner yesterday. (Is that what's called the needle?)I had the feeling it may have helped a little but think that's not the right place to spray it. Thanks

 

[Fredfloat]

OK. Now I read that the needle is in the carb. How about if I spray carb cleaner after the fuel filter. By the way I just saw the fuel line , where I attached the new fuel filter has a crack in it. I don't see fuel leaking but now have to see if I can replace it by myself. Could that have anything to do with my overall problem?

 

[Fredfloat]

Replaced the fuel line but just had time for a short run. Still not smooth but will try again next chance.

 

[Fredfloat]

That motor once started up will keep running no matter if the battery is having discharging issues. Age is age and 14 years are 14 years, worse if has sat in the water in a dock slip according to your post. Moisture will screw any electrical or elctronic part over time. What screws up any motor is not being run from time to time over time and where has been kept for all those years.

Check if someone can lend a Ignition Coil to swap and test while the combo runs on water at speed. If OK buy a new IC and save lots of cash by not taking the motor to nearest dealer. Would hate to pay $100 an hour for electrical testing..

Clean carb, check fuel pump cond if fuel starvation is suspect and make another test run at speed, if with no avail it's an electrical issue. A spark can jump properly when tested at neutral and 0 load, other scenario is jumping properly when the motor is at load say running midle to full throttle grip...

Happy Boating

Thanks for the reply. Yes, that's the point of trying to see what I can do myself (even with my very limited mechanical experience) is to avoid going to the local dealer... only place I know. They will like fix it but you have to leave it for a week (sitting uncovered) until they get around to it and then will charge you top $. They were expensive before, but have since been bought by Bass Pro, who also bought the other boat dealer in the area Caballas, so competition is pretty scarce. No way to borrow a coil from anyone I know. I'm going to built that spark tester you suggested when I get a chance. Actually now's the best time of year for fishing so I can get around well enough with half speed and the trolling motor for the next few weeks and keep doing small things to see if I can get it going.

 

[Sea Rider]

To narrow the troubleshooting has the carb been disassembled and inspected to look for gunk, 2 stroke oil hardened leftovers in the fuel passages ? A fouled carb also gives such mentioned symptoms specially when running middle to wot rpm when more fuel intake is in demand.

Fabricate the recommended Ignition Coil spark tester and check if the arcing between those two points mentioned distance are even and strong enough to be seen. If not even change the IG unit, if found even...

The test will not indicate if the motor has already an internal electric/electronic component that fails due to a degraded component, heats up, shorts inside the CD or IG when throttle is in demand while the motor misses or hesitates badly. Self cures when the component has cooled down for some miuites to start the whole frustrating PITA process again. How much would a new CD and Ignition Coil cost ?

Happy Boating

 

[Fredfloat]

To narrow the troubleshooting has the carb been disassembled and inspected to look for gunk, 2 stroke oil hardened leftovers in the fuel passages ? A fouled carb also gives such mentioned symptoms specially when running middle to wot rpm when more fuel intake is in demand.

Fabricate the recommended Ignition Coil spark tester and check if the arcing between those two points mentioned distance are even and strong enough to be seen. If not even change the IG unit, if found even...

The test will not indicate if the motor has already an internal electric/electronic component that fails due to a degraded component, heats up, shorts inside the CD or IG when throttle is in demand while the motor misses or hesitates badly. Self cures when the component has cooled down for some miuites to start the whole frustrating PITA process again. How much would a new CD and Ignition Coil cost ?

Happy Boating

Ill check around for a good youtube video on how to take the carb apart. If somebody could recommend one for my motor that would be great. Ill check prices for those other things. Thanks

 

[dadofemily]

At speed, when the motor is dying, spray gas directly in the air intake of the carb. If the motor responds positively, it is a fuel starvation problem. There is a float on the bottom of the carb that actuates a needle on a seat to open and let gas in. I am not familiar with your exact engine, but they're all similar. Look up a parts diagram for your engine. Look for "Float" or "needle" . These are the parts you would need to get to. In my case there was crap in the "seat" where the needle went in.

Jeff

 

[Fredfloat]

At speed, when the motor is dying, spray gas directly in the air intake of the carb. If the motor responds positively, it is a fuel starvation problem. There is a float on the bottom of the carb that actuates a needle on a seat to open and let gas in. I am not familiar with your exact engine, but they're all similar. Look up a parts diagram for your engine. Look for "Float" or "needle" . These are the parts you would need to get to. In my case there was crap in the "seat" where the needle went in.

Jeff

Couldn't really grasp the manuals I saw. I'm extra basic as far as motors go. I was all set to bring it in to a non dealer repair place that I used years ago (with mixed results). Then I brought it in and picked it up the same day. This time the guy said I had to leave it and it could take 10 days. Prices similar to dealer.Also sitting out in the open. Since it's still the the main fishing time of the year I 'll try to see if I can do a few more things. I've attached pictures of the motor. Is the air intake shown ? On one I put A,B,C,D. in case someone who might point out where it is isn't used to putting text on photos. If they are near the air intake could someone say which one? Also, I put a high concentration of 98 octane and Seafoam. I put it in a mason jar so I could use a small amount of gas. After using the bulb I saw this residue in it that was a kind of plastic . I cleaned it out and later saw some more. So is it that my hose from the gas tank is deteriorating? Thanks for any info.

 

[Fredfloat]

By the way, the gas+seafoam didn't do anything. It's going slower than ever...about 1/4 max. I'd still like to give carb cleaner a shot if I can figure out where to spray it. Plan on having it repaired but would like a little more speed to finish out fishing season.

 

[Fredfloat]

OK. Found out where the air intake is. A guy out fishing showed me. It's where I sprayed carb cleaner before but the motor immediately died so I thought I'd done something I should be doing. This guy knew some things about motors and as I brought the throttle up as far as it would go he made short little sprays. It seemed to be getting somewhat better. Just tried it for a bit so looking forward to do it more on my own.

 

[Fredfloat]

From the last post ... should have been "so I thought I'd done something I shouldn't have been doing" instead of "I thought I'd done something I should be doing". I tried spraying carb cleaner while the motor idled. It was really revving at times. I was starting to get nervous it was revving so much. Then I took it out and it was only a little better. Next time I'll ask someone to spray it while moving. Hope that does more. Still wonder about that tubular residue that came out of the bulb line.

 

[The Force power]

What kind of Carb-cleaner are you spraying in while running?
Most carb-cleaners clean but do not contain lubricants!
if that's the case don't do that because the engine is not getting lubrication it needs!

The carbs. will need cleaning but not that way, you will need to take it off the motor and disassemble clean & blow-out

 

[racerone]

This is a 4 stroke motor !!-----No issues with lubricants in a spray !!----Spraying a carb cleaner into the throat does not clean the working parts of the carburetor.----Take it apart for cleaning !------Test compression .----Check valve clearance.