RPM Bouncing up and down and then boat shutting off....

« **on:** March 01, 2009, 05:08:42 PM »

So 2 weeks ago we bought our first boat...jet boat. The day we bought it, it ran great and strong all day. A constant 5000-5100 RPM's all day.

Today we went to Lake Elsinore to get practice and have some family fun and the first 3 laps around it ran normal like before, on the fourth lap the RPM's would randomly and suddenly drop from 4900 to 3500 and back up and then the boat would just shut off. It was like it was starving for fuel by I had 1 full tank and the tank I was running from was 3/4 full. What could be happening? Also, how do I know if my secondary in the carb is working properly? Does anyone know where I can take my boat to get serviced? I want to get her back out on the water ASAP!!

PLEASE HELP!! I'm a complete newb and a total retard when it comes to stuff like this.

Thanks in advance!

Greg Reader

« **Reply #1 on:** March 01, 2009, 05:16:32 PM »

sounds to me like maybe your coil is on it's way out the door, or maybe just a loose wire?

« **Reply #2 on:** March 01, 2009, 05:16:51 PM »

Sounds like something easy well get you back in the water .check for lose wires behind the ignition or coil,turn the key on boat not running move the wires around and watch the tach to see if it jumps.

« **Reply #3 on:** March 01, 2009, 06:12:00 PM »

Thanks guys!! I'll try that all tomorrow after I get home from work....I'll let you know how it goes!

Greg

« **Reply #4 on:** March 01, 2009, 06:52:24 PM »

Thats got vaporlock or fuel restriction written all over it....My .02c.

GT

« **Reply #5 on:** March 01, 2009, 07:38:41 PM »

Elsinore brings out gremlins

If you're running an electric fuel pump, check the wiring closely. I had a similar problem with a broken wire behind the dash.

If your boat still has the original wiring you need to make sure it is well supported so it can't move around much, because after 30+ years it will break easily.

« **Reply #6 on:** March 01, 2009, 08:30:13 PM »

Hmmm.......the RPM's in my boat went up and down just before a rod decided to exit the block

« **Reply #7 on:** March 02, 2009, 01:25:18 PM »

OUCHIE cj

« **Reply #8 on:** March 02, 2009, 06:58:51 PM »

CJ that SUCKS a BIG ONE!!!

So I got home too late to work on the boat cause my son had a scrimmage baseball game...tomorrow will be the day to work on the girl. So, check for loose wires...fuel filter...fuel lines...what else?? What is vaporlock? Like I said I'm a mechanical retard...but only cause I've never tried working on engine type stuff. I can design ashplat like no ones business though! HAHAHA My friends at work said I needed a hobby.... sad.

« **Reply #9 on:** March 02, 2009, 07:09:43 PM »

Quote from: snuff630 on March 02, 2009, 06:58:51 PM

CJ that SUCKS a BIG ONE!!! So I got home too late to work on the boat cause my son had a scrimmage baseball game...tomorrow will be the day to work on the girl. So, check for loose wires...fuel filter...fuel lines...what else?? What is vaporlock? Like I said I'm a mechanical retard...but only cause I've never tried working on engine type stuff. I can design ashplat like no ones business though! HAHAHA My friends at work said I needed a hobby.... sad.

Vaporlock is when you get air in the lines from something getting the fuel hot? GT is this correct? ASPHALT I dump a lot of asphalt at work never designed anything

« **Reply #10 on:** March 02, 2009, 07:34:49 PM »

You aren't really holding the boat wide open all day are you???

« **Reply #11 on:** March 02, 2009, 07:35:25 PM »

Not to get off topic...but where do you work??

« **Reply #12 on:** March 02, 2009, 07:49:11 PM »

Quote from: snuff630 on March 02, 2009, 07:35:25 PM

Not to get off topic...but where do you work??

City of Rancho Cucamonga

« **Reply #13 on:** March 02, 2009, 07:52:09 PM »

Nice! I did alot of work out there a long time ago... Now I'm with a supplier... Vulcan Materials Company.

« **Reply #14 on:** March 02, 2009, 09:00:59 PM »

Quote from: boost on March 02, 2009, 07:09:43 PM

Vaporlock is when you get air in the lines from something getting the fuel hot? GT is this correct? ASPHALT I dump a lot of asphalt at work never designed anything

Close enough boost, vapor lock can occur when the fuel reaches a vapor point or boiling point, does not really mean there is heat but that the pressure dropped below its boiling point and the pump won't pump vapor, so she starves to death...

GT

« **Reply #15 on:** March 02, 2009, 09:10:16 PM »

So in essence...it Vaporizes.... HAhaha

« **Reply #16 on:** March 02, 2009, 09:14:19 PM »

Quote from: electrowoman on March 02, 2009, 07:34:49 PM

You aren't really holding the boat wide open all day are you???

Not quite sure what you mean Electro.... I just know it was embarrassing after riding on my neighbors Eliminator Daytona O/B at 80mph and then saying hey lets go for a ride and it did that crap to me.

« **Reply #17 on:** March 03, 2009, 04:18:09 PM »

Ok guys...and lady

back to the original topic. Here's some pic's I just now took....where AND what do I start with?? This first pic, I added an arrow pointing at a spark plug wire that was touching the connection but not secure like it should be...could that have been the culprit? So here's the pic's...where do I go from here?? and don't say scrap the chevy for a ford! HAHAHA

« **Reply #18 on:** March 03, 2009, 04:19:28 PM »

some more pic's...and if you need more tell me what to take pic's of....

« **Reply #19 on:** March 03, 2009, 05:49:57 PM »

I don't see a water separating fuel filter, also I would modify/replace the dizzy, thats an automotive delio, there could also be the small fuel filters in the carb bowls, I would check it out...

GT

« **Reply #20 on:** March 03, 2009, 06:06:16 PM »

I would say that yes, the plug wire not being 100% connected probably had a bit to do with your lack of performance, along with the things you've already found. Set your timing @ 36* total and give it a rip. I don't think your dizzy knows it's in a boat, so it's probably just fine.

« **Reply #21 on:** March 03, 2009, 06:07:56 PM »

Quote from: Luckie Stiff on March 03, 2009, 06:06:16 PM

I would say that yes, the plug wire not being 100% connected probably had a bit to do with your lack of performance, along with the things you've already found. Set your timing @ 36* total and give it a rip. I don't think your dizzy knows it's in a boat, so it's probably just fine.

True, but closed engine compartment would make me nervous....

GT

« **Reply #22 on:** March 03, 2009, 06:11:14 PM »

And YES your dizzy is at the wrong end

could be the culprit

« **Reply #23 on:** March 03, 2009, 06:41:40 PM »

Hahaha ok guys... back to basics... remember i'm the slow kid on the short bus and you're making me dizzy with all this dizzy stuff.

WHAT is the DIZZY?? HAHAHA but seriously??

« **Reply #24 on:** March 03, 2009, 06:48:32 PM »

Quote from: snuff630 on March 03, 2009, 06:41:40 PM

Hahaha ok guys... back to basics... remember i'm the slow kid on the short bus and you're making me dizzy with all this dizzy stuff. WHAT is the DIZZY?? HAHAHA but seriously??

dizzy is short for distributor.

snuff630

Luckie Stiff

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