Idle going higher - Ford Indmar 351

[ross_larter]

Hi, I have a Ford Indmar 351w 5.8l v8 direct drive (1991) raw water cooled.<br /><br />When running yesterday the idle rpm was 1400 when it is normally about 950rpm. It started fine the first time, but when I turned the motor off and tried to restart it, it turned over very slow like a flat battery, after a few tries it started ok and runs fine apart from the high RPM at idle. Also when running the voltage gage is at 11 volts and I think it is normally higher than that.<br /><br />Any ideas?<br /><br />cheers<br />ross

 

[Mischief Managed]

Re: Idle going higher - Ford Indmar 351

Sounds like two problems. Test the charging system for the low voltage problem. May be as simple as a loose connection.<br /><br />The high idle could be as simple as a sticky cable or a stuck choke. My money's on a choke issue.

 

[ron7000]

Re: Idle going higher - Ford Indmar 351

for the idle, first make sure the throttle linkage isn't screwed up like was said. The idle adjustment screw on the throttle mechanism on the carb should hit its stop, so visually check and make sure it does. Turn the idle screw counterclockwise with your throttle at idle, if the idle doesn't lower or change at all it's most likely a vacuum leak. Make sure if there's a pcv hose from the valve cover to the base of the carb that it's connected and not leaking (sucking) air. And make sure the pcv valve in the valve cover is a pcv valve and not an open tube.<br /><br />For the 11v on the voltage gauge, that means your alternator isn't charging. Could be broken wire but it's probably a bad alternator. You can also try reving the motor in neutral, up to 2000-3000 rpm quickly, that sometimes gets the alternator charging. If it does then you may be able to get by like this for a little but it's a clear indication your alternator is in need of service.

 

[ross_larter]

Re: Idle going higher - Ford Indmar 351

Would the slow starting and no charging fault be caused by the same thing, I assume they use the same circuit as there is only 2 connections from the battery, I think I will do clean up all the battery terminals and engine earths and try it again.<br /><br />rossl

 

[ross_larter]

Re: Idle going higher - Ford Indmar 351

Wire on back of alt was rusted through! Re soldered and all seems fine.<br /><br />rossl