Cutting out at idle, missing after idle |
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brawler
Newbie Joined: July-04-2011 Location: Lake Norman NC Status: Offline Points: 10 |
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Posted: July-11-2011 at 11:02am |
Hey guys, im having problems with my newly purchased San Juan.I ve taken her out twice for 3 hours each time. The boat had about 1/4 tank, 8-10 gallons in it when i bought her and i put 12 in the first dayand ran back down to 1/4 and then 18 yesterday and ran it back down to 1/4. I can only assume the gas that was in her was old. I know they used stabile and so do I.
My problem is that when the boat has been run awhile and then we try to idle or cruise very slow she starts to miss, almost sounds like a motor with a cam. It also happens if i cut her off and sit for a while. My best guess is that when i first get to the lake the fuel, bad and good is all mixed up and she runs fine but after sitting still or idlling the bad gas, sediment, water, whatever starts to fall down near the fuel pickup. When she dies its hard to restart. As long as i keep her reved up she seems alright. Im gonna replace the fuel filter/water separator. Otherwise boats running good. Shaft seems to have a little wobble at idle speed. Small leak at the raw water intake. Any advice or ideas would be appreciated. Thank for your time. |
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8122pbrainard
Grand Poobah Joined: September-14-2006 Location: Three Lakes Wi. Status: Offline Points: 41045 |
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Michael,
From your description, it soulds like the engine is flooding at idle. When warm and it's hard starting, does opening the throttle all the way help? This gives the engine more air and is the way to clear out a flooded engine. Is there gas dribbling down the throat of the carb? If so, it sounds like it's time for a carb rebuild. Have you tried adjusting the air mix screws? What RPM is it set to when idling? |
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brawler
Newbie Joined: July-04-2011 Location: Lake Norman NC Status: Offline Points: 10 |
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Thanks for the reply Peter. I dont know much about carbs but im gonna download that carbinfo. I thought it might be loading up at first. After iddling when i accelerate up to plane, and for the next couple minute it continues to miss. Is that consitent with to much gas. When we staled trying to dock at the ramp i Did just what you said and gave it full throttle and as i turned it over pulled the trottle back to neutral. I could always get it to start like that but after a couple repitions i killed the old battery. I think id rather have carb problems than gas problems. Thanks Peter.
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BuffaloBFN
Grand Poobah Joined: June-24-2007 Location: Gainesville,GA Status: Offline Points: 6094 |
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Sounds like what you're describing is when the engine is close to hot. Impeller? Other cooling issue? What's the temp looking like?
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TX Wind
Senior Member Joined: March-29-2011 Location: near Dallas Status: Offline Points: 334 |
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Could be a host of things. I've been having a similar problem and found some vacuum leaks and fuel fouled plugs. One leads to the other. Check for vac leaks and then pull the plugs to see how they look. If they are fuel fouled, replace them, set the points and then work your fuel air mixture over.
I've been having some issues with the ethanol in alot of the fuel these days as well. Could be like Pete says, a carb that needs reworking. |
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brawler
Newbie Joined: July-04-2011 Location: Lake Norman NC Status: Offline Points: 10 |
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Engines running 145-160, oil presure is 60 + cold and 40-50 under load warm. Before the oil change the oil smelled a bit gassy so im gonna change the plugs and fuel filter and run her again on wed night. Any way to test the carb to see if it needs help. Im gonna see how it goes. thanks guys
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TX Wind
Senior Member Joined: March-29-2011 Location: near Dallas Status: Offline Points: 334 |
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Not really, although like Pete said, fuel shouldn't be trickling out of the carb. Just got to rule out the alternatives. Get some Berrymans carb cleaner or even water and spray around the base of the carb and the hoses going into it while the engine is running. If the engine stumbles or revs up, you have a vacuum leak. Check the manifold also where it attaches to the heads the same way. Once you've ruled out a vacuum leak and bad plugs, check your points and set them. If you still have this problem at this stage, setting the air mixture on the carb is next. If you still have a problem, it is time to have someone good with carbs go through it.
Other items you might look at as well, the plug wires, a weak coil, a bad distributor cap and rotor. All of these things should be done before the carb anyway so you've got nothing to lose by doing them. |
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brawler
Newbie Joined: July-04-2011 Location: Lake Norman NC Status: Offline Points: 10 |
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Guys thanks for the help. Since last post i have run maybe 20 gallons thru the san juan and she is loading up less. Idle has improved even when hot. I have new plugs and a tune up kit but i think the plugs will do it. Thanks for your help. Michael
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81nautique
Grand Poobah Joined: September-03-2005 Location: Big Rock, Il Status: Offline Points: 5780 |
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Check to see if your choke is fully opening once hot, if not it will load up at low rpm's.
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You can’t change the wind but you can adjust your sails
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