40 bigfoot 4 stroke 1998

[lobsterfisher]

hope someone can help starts fine runs fine for the same distance each time then it startsloosing powerif u slack the trodle it idles fine if u shut the motor down and re start u get the same distanceand looses power you get 5 to 6 minutes before this happens plugs were changed coiles checked wondering on fuil pump or carbs hope some one got some advice thank u

 

[WillyBWright]

Re: 40 bigfoot 4 stroke 1998

Sounds like a venting problem. Is the vent open on the fuel tank? Other possibilities include sticky check valves in the primer bulb, and fuel pump.

 

[JB]

Re: 40 bigfoot 4 stroke 1998

Howdy, Lobsterfish.<br /><br />Welcome to iboats. <br /><br />This is the NON-repair forum. I will move your post to the Merc Outboard troubles forum.

 

[Silvertip]

Re: 40 bigfoot 4 stroke 1998

Is the engine overheating? Good water flow from the tell-tail? No water flow = no cooling = overheat = loss of power. Continue this process and you may end up with severe engine damage. Does squeezing the primer bulb help when the engine loses power? Try pushing the key in (activate choke) momentarily when this happens. If engine picks up its a fuel delivery problem. Either clogged lines, tank pick-up, filter, gummed up carbs, sticky needle and seat, etc.

 

[lobsterfisher]

Re: 40 bigfoot 4 stroke 1998

it gets lots of vent tried squeezing primer ball makes no didderenceit as good water flow it doesnt seam to get hot when u shut it down it only takes a second and it runs fine for a little while i was thinking it could be jumping spark or a problem in the fuel pump it as manualstart and a auttomatic choke so far thanks guys great site

 

[Silvertip]

Re: 40 bigfoot 4 stroke 1998

Sounds like a fuel pump going bad.

 

[MercFan]

Re: 40 bigfoot 4 stroke 1998

Fuel pump, but if you pump the primer bulb while it's dieing it should go like stink again. If the bulb stays flat and doesn't want to expand, it's a fuel line problem.

 

[lobsterfisher]

Re: 40 bigfoot 4 stroke 1998

all great advice the only problem i tried all of these suggestions the problem with taking it to the shop is that it needs to be running for about 10 minutes before this problem occurs only way to find promlem is to run the motor on a boat for 10 minutes or so until it breaks down the shop dont have the ficilities to do this if it gave out completely it would be easier to findit seams like a smsll problem but as caused alot of headackes if anyone as any more suggestions it would be greately appreachited sorry about the spelling and typing tipical newfie lol

 

[lobsterfisher]

Re: 40 bigfoot 4 stroke 1998

what a challange somethind so small cause so much trubble tried all suggestions no luck the motor runs fine for about 10 minutes then takes a fit it sputters no power but idles fine shut down motor just long enough to say it stoped start it up it runs fine for another 10 minutesthen acks up again just like clock work looking for some suggestions

 

[planetech]

Re: 40 bigfoot 4 stroke 1998

did you ever find out the solution to your problem? I have a 25 bigfoot 03 that is doing exactly the same thing. I am thinking it is the seal on the watertube under the powerhead.

 

[Faztbullet]

Re: 40 bigfoot 4 stroke 1998

Any alarms? A defective oil pressure switch,temp switch or low on oil will cause engine to do this, when you stop and restart you reset the ECU.

 

[planetech]

Re: 40 bigfoot 4 stroke 1998

No alarms but the motor is a tiller manual start so I don't think it has any. You don't really have to stop and start just go to idle for a couple of minutes and then it is fine for awhile and then it rolls back again. the pee stream is strong when first started and then as it warms up I guess the thermostat opens and the stream gets weak.