3.7 stalls at idel after warmed up

[69bertramsf]

Hi, my names tony new to Iboats. I have a problem with my 3.7 and can figure it out. It starts write up fine I pull it up on plane and cruz for 30 min. Or so and come back to a idel and after about 5 min. It will stall every time and wont start back. Unless I let it set for at least 30 min. Its not running hot and just rebuilt the carb. Any suggestions?

 

[Oshkosh1]

Re: 3.7 stalls at idel after warmed up

COMPLETE rebuild(tanked, ALL new gaskets, float, pump etc...)?
Did you ensure that ALL passages and jets were blown out with air?

Even the tiniest of blockages can cause big problems.

Was this a problem prior to the rebuild?

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Yeah rebuilt the whole cab from top to bottom. And the same issue after the rebuild im starting to think the coil is getting to hot and breaking down but I don't know

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

But I doest make sense if it was in the carb. U would think it would do it all the time rather than just when the motor warms up

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Is there anyone out there that'd had the same problem?

 

[Don S]

Re: 3.7 stalls at idel after warmed up

Plugged fuel tank vent, fuel pickup tube in the tank plugged, antisiphon valve plugged.

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Fuel tank vent is clear it will run fine all day at 2500-3000 rpm it's only at about 1200to that it stalls

 

[bwthor]

Re: 3.7 stalls at idel after warmed up

But I doest make sense if it was in the carb. U would think it would do it all the time rather than just when the motor warms up

Mine is doing the exact same thing. Once it warms up, I can't get it above idle. I'm about 99% sure it isn't charging properly, and is only running off of the battery. Once it warms up and the battery voltage drops some, the electrical system is also requiring more. What is your voltage reading? Mine is showing at just above 12, which isn't enough.

Anyone know how to test if it is that crankshaft mounted alternator or the voltage regulator?
I pulled the negative wires off of the battery while it was running and it died.

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

And the coil is getting vary hot, the points have been switched over to electronic ignition

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Mine is reading 14 volts. I have a singe wire alt. And made a bracket

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Is your hard to start after it stalls?

 

[bwthor]

Re: 3.7 stalls at idel after warmed up

Is your hard to start after it stalls?

Yeah, a bit harder, but not terrible. It will start and idle, but as soon as I start giving it any throttle, it starts to miss and just runs flat. If I can get it to rev enough, it usually comes out of it. It is really bizarre, and I can't duplicate it at home running on the hose. Usually happens when I'm towing the tube at slow speeds for a while and it heats up a bit.

I've tried different points, condensor, coil carb rebuild and no luck. Let it sit for a bit with the cowl off, and it runs fine again. The longer I go in the day the worse it got, and the lower the voltage would get. I think it was charging some, but not enough.

I decided to go the new alternator route as well, so I ordered one a few hours ago. Hopefully I can get this thing going. Next move is to bring a big drill bit with me and sink it!

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

Yeah I know I have 2 3.7s in my 1969 Bertram

 

[a1nowell]

Re: 3.7 stalls at idel after warmed up

69bert,
Look at this thread I posted 6-8 weeks ago it may help.

Larry

http://forums.iboats.com/showthread.php?t=541400&highlight=a1nowell

 

[69bertramsf]

Re: 3.7 stalls at idel after warmed up

It was the coil. I replaced the coil yesterday and ideas great now!

 

[bwthor]

Re: 3.7 stalls at idel after warmed up

It was the coil. I replaced the coil yesterday and ideas great now!

Good news! I just finished installing a marine alternator since it wasn't charging. I also installed a new coil while I was working on it. Hopefully all will go well when I get out to the lake.