PDA

View Full Version : Why Won't It Idle???



FlatRacer, aka BarrelBack
07-04-2004, 02:07 PM
Okay, my boating season is not getting off to a great start. I have two boats that just won't idle. :bonk:
First is my '67 Donzi repowered with a 302 Ford, Holley Vacuum secondary 4bbl, ???cfm, dual point distributor.
Second boat is our '38 Chris Craft replica with a 4.7L Buick V6, 390 cfm Holley 4bbl, single point distributor.
Both boats have the same problem. They run fine at speed, but as soon as I drop the revs below 1000rpm, the engine dies. :banghead:
So what, in general causes an engine not to want to idle? Too much timing, not enough timing, point dwell,...what?
I feel like an idiot for asking because I should know this stuff, but I need help. :embarasse
Oh, and my other problem with the Donzi is I've never found the timing pointer or tab on the engine, so God know where the timing actually is.


Thanks,
Eric

Ed Donnelly
07-04-2004, 02:29 PM
Did you use fuel stabilizer in the fall, and did you run the engines so the stailizer got into the carbs? Sounds like your idle circuits are gummed up.....Ed

penbroke
07-04-2004, 02:56 PM
What Ed said.

Timing pointer can be had from cjponyparts.com. They are an after market Mustang parts supplier. I would expect the closest boneyard might produce one as well. I thought Rootsy had one for ya?

Frank :wavey:

BUIZILLA
07-04-2004, 03:02 PM
Hi, welp at some point the engines have :wink: to idle, or you wouldn't be able to start them and get them in gear, and away from the dock, in the first place. So, with that being said.... (1) is the 390 and 600 carb both marine SPECIFIC, meaning NO vacuum nipples? now, turn each idle MIXTURE screw in to slightly bottom, and back out 1 1/2 turns for starters, run the engine at 800 rpm, and adjust those in and out, one at a time, 1/4 turn at a time, for best idle rpm. Stabilize the idle at 800, in neutral, after adjustments. (2) incorrect dwell setting of the single/dual points, can definately do the same symptom as well. I'd be VERY worried, if there is guesstimate timing of the one engine going on...

JH

FlatRacer, aka BarrelBack
07-04-2004, 04:49 PM
The "Idle Mixture Screw"!!!!

Duh!!! :cistineb:

It worked on the Chris. We'll see tomorrow if it works on the Donzi. Too pooped to pop right now.

Thanks Buizilla!

FR (freakin' retard) :bonk:

FlatRacer, aka BarrelBack
07-04-2004, 09:24 PM
Hey, it worked on the Donzi too. Just got back from watching the fireworks on the lake with my wife and cousin. Ran like it's supposed to.

Thanks again, Buizilla.

FR

Frank, what are you doing later this week or next weekend? I'll call you tomorrow.

Eric

MOP
07-04-2004, 09:25 PM
The pointer on the Ford is a bugger to see on the 16, I was lucky mine had a big plastic pop out hatch to work on the front, belts. tensioning and timing. The pointer is at about 2 O clock on the port side damn near touching the balancer, it may be missing. If so I am am pretty sure you could carefully drill with an angle drill then tap for a 3/16 thread and screw in a 1-1/2" long screw with Loc Tite that the head was cut off and ground to a point. The timing marks are on the balancer. pull the coil wire and tap it over slowly until you find the marks, try to use white to mark them. If for some reason all you can find is the TDC slot buy a degree/timing tape and stick it on.

Phil

MOP
07-04-2004, 09:44 PM
Eric A P.S. to the last post if you are not real comfortable trying to drill for a new (if missing pointer the pointer) another method is to make a 90 degree tab and use two timing cover bolts at about 2 O clock to secure it close to the balancer 3/16 to 1/4" away. It should not extend more than 1/4" over the edge to be able to see the marks. Once in place use a piston stop to determine exact TDC, mark the tab by filing a small V grove. You may have to R&R to file notch Timing on marine is far more critical on marine than other engines.

Phil

FlatRacer, aka BarrelBack
07-05-2004, 03:08 PM
Somebody last year mentioned a "whistler" device that screws into the spark plug hole and makes a whistling sound as the piston comes up that stops when the piston reaches the top.
Anyone know where I can order one of those?

Eric

MOP
07-05-2004, 03:56 PM
I think Jim posted that, me being so old I have only seen one! I have been told they work great, wish I had them years back OHV engines tend to bend the piston stop unless you are super careful.

Phil

MOP
07-05-2004, 04:00 PM
Did a search found many here is one!

http://www.thetoolwarehouse.net/shop/STR-TU17PL.html