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roush611
06-07-2013, 02:03 PM
I'm trying to get this damn boat to idle at around 6-7 but according to the tach it is bouncing between 8-1000 right now. Just by listening to it I feel that it is idling way lower then that. In order to get it to idle where it is now I am 3.5 turns out with the mixture screws. Is there a possibility my tach is off because to me it seems like it is idling way below 8 right now. Here is a video for reference.

Carb was just rebuilt
Timing is set at 10 btdc

http://youtu.be/iZByyKo043Y

Double D
06-07-2013, 02:06 PM
It sounds sweet, leave it!! :rolleyes::D

CantRepeat
06-07-2013, 02:09 PM
I'm trying to get this damn boat to idle at around 6-7 but according to the tach it is bouncing between 8-1000 right now. Just by listening to it I feel that it is idling way lower then that. In order to get it to idle where it is now I am 3.5 turns out with the mixture screws. Is there a possibility my tach is off because to me it seems like it is idling way below 8 right now. Here is a video for reference.

Carb was just rebuilt
Timing is set at 10 btdc

http://youtu.be/iZByyKo043Y

Did you use a vacuum gauge to get max vacuum while adjusting the mixture screws?

roush611
06-07-2013, 02:34 PM
Did you use a vacuum gauge to get max vacuum while adjusting the mixture screws?

No I was just doing it by ear. I know I should use a vacuum but I don't have one at my disposal right now unfortunately.0

catamount
06-07-2013, 02:47 PM
That is a really low idle. I'd guess 600. I wonder if you have ground issues behind the dash (common!) causing tach inconsistencies. 3.5 turns out seems very rich, but like they say... ..."feed it what it wants".

How does it start when warmed up? How does it start when cold?

roush611
06-07-2013, 02:53 PM
That is a really low idle. I'd guess 600. I wonder if you have ground issues behind the dash (common!) causing tach inconsistencies. 3.5 turns out seems very rich, but like they say... ..."feed it what it wants".

How does it start when warmed up? How does it start when cold?


Starts right up with a bit of gas when warm. Cold starting is no good but that is also due to the fact that I cant get the damn choke right. I can't find anywhere with instructions on proper spring installation on that thing. I think it is in there right but I dont know for sure.

j.mccreight@hotmail.com
06-07-2013, 03:10 PM
idle speed should be around 600 rpm in gear which equals around 800 rpm in neutral

thatsmrmastercraft
06-07-2013, 03:16 PM
At 3.5 turns out you are way too rich at idle if the carb was rebuilt properly. Did the carb get soaked long enough? Overnight is about a minimum with the new carb cleaners.

You can get a situation where the idle speed screw is out too far and you compensate with the idle mixture screws. You end up idling partially on the main metering system and it doesn't work well. I would set the mixture screws at 1.5 or 1.75 and try to work with the idle speed screw to get good results. You can adjust the mixture screws to attain highest idle speed, but you have to be close with the mixture screws to do that.

If that doesn't work, I would remove the mixture screws and insert the plastic tube from a can of carb cleaner in and clean the passage out (with the engine off, of course).

To set the choke, turn the choke housing so the choke blade just closes on a completely cold engine. If it doesn't open fully in approx. 90 seconds, you may need to replace the choke cap. Check that you have battery voltage to the cap and that the ground is good.

This assumes that all the basics are in order: plugs, cap, rotor, points (?), timing, plug wire, pcv valve, carb base gasket, fuel filters....

catamount
06-07-2013, 03:42 PM
thatsmrmastercraft, check out that video. What RPM do you think that's idling at? It sounds nice to me!

thatsmrmastercraft
06-07-2013, 03:45 PM
thatsmrmastercraft, check out that video. What RPM do you think that's idling at? It sounds nice to me!

That does sound good. I would check the idle speed with a remote tach verified to be somewhat accurate. There is a problem yet if the mixture screws are at 3.5 turns out.

roush611
06-07-2013, 03:59 PM
The carb sat well overnight in the cleaner. After I took it out I sprayed every part with the can of carb cleaner.

I will start from scratch with the mixture screws again. The problem i am having is with the idle mixture screws at 1.5-1.75 turns out the boat will not idle lower that 1000.

I will check back in a bit after I play with it a bit.

roush611
06-07-2013, 09:52 PM
Here is a little update. It is idling at supposedly 1k right now. If I drop it any lower with the idle acre it gets pretty rough. I am at 2 turns out right now. What so y'all think? I am having one issue though if I try to rev it fast it hesitates and almost stalls. If it accelerate at a normal pace every thing is fine. I am thinking the accelerator pump is just not tuned right?

Here is a quick video of the new idle.

http://youtu.be/O0qLgFPNDT0

thatsmrmastercraft
06-07-2013, 10:53 PM
Spray around your carb base gasket and look for a vacuum leak. Confirm that the firing order is correct. Having two wires crossed can give you this effect (don't ask how I know). Are you still running points or have you changed to electronic ignition?

roush611
06-07-2013, 10:59 PM
Spray around your carb base gasket and look for a vacuum leak. Confirm that the firing order is correct. Having two wires crossed can give you this effect (don't ask how I know). Are you still running points or have you changed to electronic ignition?

Firing order is correct. I have checked a million times ha ha. I am still running points, they are pretty much brand new because I bought a whole new Mallory distributor. I will be upgrading it next summer to the E-spark. The budget just didn't allow for an EI unit at this time.

I might go buy some new plugs tomorrow. By now these plugs have been through a lot the last few weeks. Running rich then lean then super rich. Would not be surprised if one of them is fouled.