70hp Johnson: dies after 10 minutes

[crispi]

Hi all,<br /><br />Wondering if anyone is familiar with this problem? Motor starts and idles fine, then dies after about 10 minutes. It seems like there's plenty of water coming out of the engine and we've tried two different fuel sources(internal tank and carry aboard tank), but with the same results. <br /><br />Thanks in advance.<br />Bob

 

[rickdb1boat]

Re: 70hp Johnson: dies after 10 minutes

Dies after 10 minutes of running or just idleing? Sounds like you may have an electrical component problem that fails when it heats up. Best way to simulate this is with a hair dryer at home while running on the muffs or in a barrel. Start it up and point the hair dryer close at the powerpack and other related electrical components. If it dies pretty quick, you've found your problem...

 

[phatmanmike]

Re: 70hp Johnson: dies after 10 minutes

are your tanks vented?

 

[crispi]

Re: 70hp Johnson: dies after 10 minutes

Originally posted by phatmanmike:<br /> are your tanks vented?

When we used the auxilliary tank the vent was open, but I didn't check on the internal tank. <br /><br />Thanks for the idea.<br /><br />Bob

 

[crispi]

Re: 70hp Johnson: dies after 10 minutes

You know your pampering your boat when you buy it a hair dryer. Thanks for the idea.<br />Bob<br /><br /><br />

Originally posted by rickdb1boat:<br /> Dies after 10 minutes of running or just idleing? Sounds like you may have an electrical component problem that fails when it heats up. Best way to simulate this is with a hair dryer at home while running on the muffs or in a barrel. Start it up and point the hair dryer close at the powerpack and other related electrical components. If it dies pretty quick, you've found your problem...

 

[68wetboat]

Re: 70hp Johnson: dies after 10 minutes

I'm curious what you mean by venting the tank. I have a 40 hp '68 Johnson that has an portable tank. Should there be some vent open on the tank so air can get in?<br /><br />I took it out for about 6 hours a week ago and it ran/started fine all day...it finally died when we were by boat ramp. I took it out again and it would run for about 2 min and then die. It was tough starting it back up...had to choke it alot and it would run for maybe 1 min and die. Any thoughts?

 

[papasage]

Re: 70hp Johnson: dies after 10 minutes

sounds like fuelpump

 

[Solittle]

Re: 70hp Johnson: dies after 10 minutes

wetboat - All fuel tanks need a vent. Most portable tanks have the vent built into the fuel cap. Many also have a screw to close the vent and if it is closed the vacume created by the fuel being pumped to the motor will eventually be stronger than the suction from the fuel pump - - and - -