75 HP 1984 (vapor lock?) Fuel Problem or ???

truhl_58

Seaman Apprentice
Joined
Aug 7, 2011
Messages
38
Here is my story 2 weeks ago I took my boat out for the first. Left the dock and started trolling ran great, trolled for about 2 hrs. than ran the boat up to about 4000rpm for 4min. up to the dock and quit all went well. Next day ran the boat at about 4000rpm for about 10 min anchored bottom fished for about 1hour started up and crused at about 3000rpm for about 5min slowed down to troll and it would not idle. Tried to start would run 10sec. died did this over and over and made to the dock and left for home (acted like it was starving for fuel bulb felt funkey) Cleaned out the fuel tank bought new preminum fuel replaced the fuel pump, check valves and fuel filter (all looked OK but replaced it anyway). Hooked up the hose pumped up the fuel line turned on the water and it started right up ran for 2min and shut it off did this about 4 times ran great every time (fired right off). Got up this morning left for the lake backed in the boat, started right up took off ran at 2000rpm for about 5min slowed down and started trolling. Trolled for about an hour turned around ran the boat up to about 4000rpm for about 3min slowed down to troll and it died. Tried to start over and over some times it would run for 3-4 sec. than die never did start. 2 miles from the boat ramp, started toward the boat ramp with an electric motor till the battery died, 1 mile to the boat ramp, started paddling for the ramp, wind came up paddled like hell till the last 100 feet from the ramp,got a tow to the ramp pulled the boat out towed it home and I am know charging the battery. All the time the motor would not start the bulb felt funney would not pump up hard. Do outboards vapor lock or what do you think is the problem ? The work on the fuel pump made no difference could it be plugs ? Any help or direction would be great. Thank You
 

CharlieB

Vice Admiral
Joined
Apr 10, 2007
Messages
5,617
Re: 75 HP 1984 (vapor lock?) Fuel Problem or ???

Can you better explain 'funkey'?

If the fuel tank vent is not open or is restricted, the fuel pump will attempt to pull a vacuum on the tank, fuel flow reduces until it virtually stops. Many motors can actually suck the primer bulb flat.
 

truhl_58

Seaman Apprentice
Joined
Aug 7, 2011
Messages
38
Re: 75 HP 1984 (vapor lock?) Fuel Problem or ???

The fuel bulb felt spongey not hard, not like it was empty. Got up this morning unhooked the battery charger hooked up the water hose and it fired up. I did not have to crank it much at all it sounded and acted like it was missing or fouled plugs ran up the rpm a little and it smoothed right out. I don't know what to think now.
 

Wingedwheel

Lieutenant Junior Grade
Joined
Jun 16, 2009
Messages
1,071
Re: 75 HP 1984 (vapor lock?) Fuel Problem or ???

It could possibly be something in your carb bowls. When was the last time they were cleaned?
 

truhl_58

Seaman Apprentice
Joined
Aug 7, 2011
Messages
38
Re: 75 HP 1984 (vapor lock?) Fuel Problem or ???

Hard to say I just bought the boat. I have not touched them. I went out side about an hour ago I turned the water hose on chocked it once and it fired right off and idled perfect. Once in a while you could here a mis fire but all and all it idled perfect. I just ordered a set of plugs. Seems like after it cooled overnight things are back to normal. Do you think heat has something to do with it ?
 

truhl_58

Seaman Apprentice
Joined
Aug 7, 2011
Messages
38
Re: 75 HP 1984 (vapor lock?) Fuel Problem or ???

Does it sound like electrical or fuel? How can you tell if you are getting enough cooling, there is a good stream from the Peehole ?
 
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