SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: 87Caliber1 on July 03, 2016, 02:04:01 PM

Title: HELP NEEDED, PLEASE??!!
Post by: 87Caliber1 on July 03, 2016, 02:04:01 PM
Ok my dad started his boat with the cover on the scoop & it ran like it had a fouled plug or choke stuck, so we got it home changed plugs & checked to see if choke was stuck on, all was good, took it out again still running like 800 RPMs shy of normal. Would this be the power valve or accelerator pump?? Any ideas or info would be great if someone has had this happen or heard of it, thanks. I hope EVERYONE HAS A SAFE & HAPPY 4th, thanks again


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Title: Re: HELP NEEDED, PLEASE??!!
Post by: Cliffjumper on July 03, 2016, 02:06:22 PM
What carb are you running?
Title: Re: HELP NEEDED, PLEASE??!!
Post by: 87Caliber1 on July 03, 2016, 02:27:48 PM
Oops sorry, its a Holley 750 double pumper-marine feeding a mild 468
Title: Re: HELP NEEDED, PLEASE??!!
Post by: Cliffjumper on July 03, 2016, 02:49:50 PM
And your getting enough fuel and timing is ok ?
Title: Re: HELP NEEDED, PLEASE??!!
Post by: 87Caliber1 on July 03, 2016, 03:05:06 PM
yeah, it sounds fine at home with no load on pump, but in the water sounds like its running on 6 or 7 cylinders
Title: Re: HELP NEEDED, PLEASE??!!
Post by: Cliffjumper on July 03, 2016, 03:46:00 PM
Sounds like a timing issue. 
Title: Re: HELP NEEDED, PLEASE??!!
Post by: 87Caliber1 on July 04, 2016, 08:48:04 AM
no timing isnt it cause if you turn it either way it wont run, we tried it at the lake
Title: Re: HELP NEEDED, PLEASE??!!
Post by: gbborn on July 04, 2016, 08:50:22 AM
Does it have a diaphragm vacuum advance if the diaphragm is torrent you won't get full rpm out of the boat


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Title: Re: HELP NEEDED, PLEASE??!!
Post by: gbborn on July 04, 2016, 08:54:32 AM
Excelerator pump works only under acceleration not at Sustained rpm


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Title: Re: HELP NEEDED, PLEASE??!!
Post by: vwagon13 on July 04, 2016, 10:38:06 AM
I'm curious, when you say "800 RPMs lower than normal", what's normal RPM? How long did you guys run the boat with your carburetor or scoop covered?
 Did the boat backfire any? I am betting it's a blown power valve. Holley's will do that when they backfire
 And I mean this with no disrespect, but how much experience do you and your dad have with this boat?
Title: Re: HELP NEEDED, PLEASE??!!
Post by: GT Jets on July 04, 2016, 11:06:28 AM
Check your distributor cap for carbon tracking.
Title: Re: HELP NEEDED, PLEASE??!!
Post by: 87Caliber1 on July 04, 2016, 03:13:18 PM
thanks for all the replies, we got it today, took carb off put another one on from my boat, it ran fine just a little rich, then fired it in the shop where it was kinda dark & saw that a plug wire was sparking against the header flange, took it out & it was melted, changed plug wire & adjusted the looms to hold wires higher & all is good!!! thanks everyone for all the replies!!! And we have quite a bit of experience with this boat & mine, we've ran jets for years, thanks, was just trying to see if someone had this happen before & new off hand, but we diagnosed it all over 1 thing at a time & got it figured out
Title: Re: HELP NEEDED, PLEASE??!!
Post by: BoatsNhoes on July 04, 2016, 06:13:47 PM

thanks for all the replies, we got it today, took carb off put another one on from my boat, it ran fine just a little rich, then fired it in the shop where it was kinda dark & saw that a plug wire was sparking against the header flange, took it out & it was melted, changed plug wire & adjusted the looms to hold wires higher & all is good!!! thanks everyone for all the replies!!! And we have quite a bit of experience with this boat & mine, we've ran jets for years, thanks, was just trying to see if someone had this happen before & new off hand, but we diagnosed it all over 1 thing at a time & got it figured out
yup that's how I have found a few shorting spark plug wires in my motors turn out the lights a fire it up" you can see the flashes  and some times in even  more than one wire " nice job 😎👍🍻


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