SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: hbkeith on March 12, 2018, 08:26:10 AM

Title: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 12, 2018, 08:26:10 AM

I bought my first jet boat a few weeks back and took it to Elsinore yesterday to test it out. Its a 19997 19.5' commander with a sportpac 454 and a quadrajet (all stock). The boat runs great and accelerates without hesitation. But when I get on it and the secondary's open it runs strong for about 15-20 seconds and then starts to die as if its running out of gas or is vapor locked. I have heard that boats with enclosed engines can have this problem so my plan is to remove the engine cover and try it out, what do you guys think? The fuel filters are new and it does the same thing regardless of which gas tank I have it running on.

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: sevans01 on March 12, 2018, 08:36:10 AM

I’m no expert, have you checked your fuel pump? Might need a new one, and probably wouldn’t hurt to have the carb rebuilt as well. My .02


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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 12, 2018, 10:09:09 AM

Yeah, I think I will try a new better quality fuel pump with a regulator and gauge.

Thanks!

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: Nickel$worth on March 12, 2018, 10:09:18 AM

Couple things.1 fuel filter, 2 fuel pump,carburetor, all if dirty, or bad, your starving the motor for gas. For myself fuel filter was the most common cause.


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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 12, 2018, 02:15:35 PM

How old are the fuel hoses?

Have you cracked a fuel cap to check for a plugged tank vent?

Fuel pumps don't last forever in this garbage we call gasoline....

Good hunting.

GT

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 12, 2018, 04:33:41 PM

I'm gonna dive into this weekend and go through the fuel system hoses vents etc. along with fuel pump replacement, gauge and regulator. Have any of you used JEGS fuel pumps?? The price is pretty good and I want to get one with more capacity in case I end up changing the carb.

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 12, 2018, 05:13:41 PM

Quote from: hbkeith on March 12, 2018, 04:33:41 PM

I'm gonna dive into this weekend and go through the fuel system hoses vents etc. along with fuel pump replacement, gauge and regulator. Have any of you used JEGS fuel pumps?? The price is pretty good and I want to get one with more capacity in case I end up changing the carb.

Covered engine?

I wouldn't use an automotive pump. I personally guarantee that stock deal won't exceed a stock pump. If you can find one, the dual diaphragm Carters are very nice for the scratch.


Holley https://www.summitracing.com/parts/hly-712-454-11 (https://www.summitracing.com/parts/hly-712-454-11)

Carter https://www.summitracing.com/parts/crt-m60601 (https://www.summitracing.com/parts/crt-m60601)

If you have ten's and twenties falling out of your butt, grab the billet Holley, but be mindful, you will need to regulate it...

HP Holley http://www.jegs.com/i/Holley/510/12-454-40/10002/-1 (http://www.jegs.com/i/Holley/510/12-454-40/10002/-1)

GT

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: TrollerDave on March 12, 2018, 07:29:34 PM

Are your floats/needle and seat adjusted properly or stuck?

Like GT said, today's gas sucks and won't last. It will evaporate and gum up pretty quickly.

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 13, 2018, 07:43:08 PM

Thanks for the input guys. Enclosed engine: front, back two sides a top and a bottom ;)

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: Nickel$worth on March 14, 2018, 06:51:22 PM

Clay Smith Cams has a high flow high pressure pump, that has 1/2" fitting. He use them on every thing from blown motors, to carburator motors. Call him a call 714-523-0530.  Terry


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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 14, 2018, 08:09:47 PM

Quote from: Nickel$worth on March 14, 2018, 06:51:22 PM

Clay Smith Cams has a high flow high pressure pump, that has 1/2" fitting. He use them on every thing from blown motors, to carburator motors. Call him a call 714-523-0530.  Terry


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He really needs to grab a marine pump... Clay Smith Pumps are not marine...   :sly:


GT

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: aquaholic72 on March 14, 2018, 11:19:04 PM

Quote from: GT Jets on March 14, 2018, 08:09:47 PM

He really needs to grab a marine pump... Clay Smith Pumps are not marine...   :sly:


GT

At the risk of sounding ingnorant gt.,  what's the difference in the marine pump?  Ive always ran a holley 110gph on my boat,  is it just a covered engine safety thing?? 

your friendly local v-drive owner

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 14, 2018, 11:27:41 PM

Quote from: aquaholic72 on March 14, 2018, 11:19:04 PM

At the risk of sounding ingnorant gt.,  what's the difference in the marine pump?  Ive always ran a holley 110gph on my boat,  is it just a covered engine safety thing?? 

your friendly local v-drive owner

Definition of a dumb question in my dictionary.
A question you answer while asking because you didn't think it through.  :thumbup:

To answer your very intelligent question, when a regular, automotive style fuel pump fails or loses a diaphragm, the fuel literally sprays out of a vent hole on the back (air) side of the diaphragm. The engine may or may not die causing an extreme explosion risk if not shut down in time.

An approved marine fuel pump has a secondary diaphragm and a vent port designed to be routed to the throat of the carburetor. In the event of a failure of the diaphragm, the fuel is pushed via the second diaphram in the sealed unit up through that port killing the engine. Eliminating the cahnce of a fire or explosion.

Hope that paints a picture for you....

GT

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: aquaholic72 on March 15, 2018, 05:53:52 AM

Picture painted!!  I had no idea there were different pumps,  coming into boat stuff from car stuff,  as always thanks gt for your knowledge..  Not to hack the thread,  but do you have a recommendation for a mechanical pump for my blown BBC,  outside of the holley I use??? 

your friendly local v-drive owner

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: aquaholic72 on March 15, 2018, 05:59:43 AM

Got it!!  Carter double diafram,  sorry got ahead of myself..  Thanks gt.. Or holley billet👍👍

your friendly local v-drive owner

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 15, 2018, 11:47:14 AM

Quote from: aquaholic72 on March 15, 2018, 05:59:43 AM

Got it!!  Carter double diafram,  sorry got ahead of myself..  Thanks gt.. Or holley billet👍👍

your friendly local v-drive owner

Yeah, that Marine billet pump is really nice. It's also completely rebuildable. Once in a while you can catch a deal on them, I saw it on Amazon about a month ago for $335. Keep your eyes peeled. They're out there.

And you're very welcome, it's my pleasure to share what I have learned over the years.

GT

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: 5150whiteboy on March 15, 2018, 12:10:47 PM

I have a spare Carter fuel pump you can use to test to help narrow down the issue in in west covina

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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 16, 2018, 07:03:34 AM

Thanks for all the input and suggestions! I have ordered an new carter marine fuel pump from JEGS that's what my marine power motor came with. I have also ordered all new fuel filters and hose. I'm thinking it might be the placement of the fuel pump though. Its basically mounted next to the dizzy on a bracket hanging off the intake manifold, that's the way marine power did it. If I still have the same issue after all the new stuff mentioned above is installed I will relocate the fuel pump low on the transom. I will be sure to post the solution when I get it to try to help others that run into this issue. Thank you for offering the tester fuel pump 5150 whiteboy!  :thumbup:

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: GT Jets on March 16, 2018, 02:31:15 PM

Quote from: hbkeith on March 16, 2018, 07:03:34 AM

Thanks for all the input and suggestions! I have ordered an new carter marine fuel pump from JEGS that's what my marine power motor came with. I have also ordered all new fuel filters and hose. I'm thinking it might be the placement of the fuel pump though. Its basically mounted next to the dizzy on a bracket hanging off the intake manifold, that's the way marine power did it. If I still have the same issue after all the new stuff mentioned above is installed I will relocate the fuel pump low on the transom. I will be sure to post the solution when I get it to try to help others that run into this issue. Thank you for offering the tester fuel pump 5150 whiteboy!  :thumbup:

So you have an electric pump....

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 19, 2018, 09:28:05 AM

Yes, its an electric pump 5-7psi

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: Supernowa on March 19, 2018, 12:02:35 PM

I had the same problem with my boat. Check the fittings that come off the tank. Mine had screens in them and they were clogged so as soon as i wooded it, it would dies

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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 19, 2018, 02:26:10 PM

I will check the screens also. Thank you!

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 26, 2018, 06:31:02 AM

Problem solved. I changed the fuel filters and replaced the fuel pump. I'm pretty sure it was the pump and not the filters because it did the same thing regardless of which tank I was pulling from. Tested it at lake Elsinore yesterday and it ran perfect. Thank you for help! ;D

Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: el mojado on March 26, 2018, 08:47:40 AM

Good to hear you got it running. I recommend running a fuel pressure gauge. If you have the same issue in the future, you can watch your pressure and see if it's normal or too low. Should be 7 psi while cruising and consistent.

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Title: Re: Engine Dies if I floor it for more than 15 - 20 seconds
Post by: hbkeith on March 26, 2018, 10:54:46 AM

Yeah, fuel pressure gauge is on the LONG list of things to do before summer lol