SoCal Jet Boats

Tech Talk => Engine Mechanical / Electrical => Topic started by: tryklon on May 22, 2010, 12:19:34 AM

Title: Mechanical convert-electrical fuel pump
Post by: tryklon on May 22, 2010, 12:19:34 AM: Hey guys,

have a problem just brought out the boat for the season and went to fire her up....turns over but nothin.. :banghead:
455 olds(stock) ,2 tanks are half filled, new gas, new edelbrock marine carb, new fuel filter, new hose running to the carb, however I did notice that the throttle is not squirting fuel into the bowls at all and the lines running from filter to the tank are dry??? Im thinkin fuel pump anyone have a better idea?

Also what is involved in switching from mechanical to electrical? and which pump should I get from summit?
Any advice would be great before memorial
Title: Re: Mechanical convert-electrical fuel pump
Post by: electrowoman on May 22, 2010, 07:35:50 AM: Sounds like you nailed it. Bad pump. I'll let the guys running electric take over from here.

I never liked the idea of an electric pump, more likely to fail. If ya don't need it I wouldn't
use it.
JMO
Title: Re: Mechanical convert-electrical fuel pump
Post by: Leadsled on May 22, 2010, 07:42:35 AM: I agree. A mechanical will cost a whopping $30 or so from the "zone" and by the time you get a good electric pump, regulator, and block off plate your looking at a lot more than a mechanical. Or you could get the summit brand mechanical and I think that will run you somewhere in the $80 range.
Title: Re: Mechanical convert-electrical fuel pump
Post by: countryboyaustin on May 23, 2010, 08:52:18 AM: My eliminator has two electric pumps/one from each tank and they run to a mechanical. I have never used the electric one except to turn em on to see if they actually work. Cool that i could limp in if the mechanical ever failed!
Title: Re: Mechanical convert-electrical fuel pump
Post by: playgrundy on May 27, 2010, 06:50:07 PM: You might also have a problem with your accelerator pump. I had this same problem at the begining of this boating season. A needle in my Holly carb was sticking and not allowing my accererator pump to squirt fuel.
Title: Re: Mechanical convert-electrical fuel pump
Post by: SS-201 on June 01, 2010, 03:18:49 AM: Agree, I run both just in case, the electric keeps the prime up.
Title: Re: Mechanical convert-electrical fuel pump
Post by: t8017e on June 01, 2010, 09:51:24 AM: Is running both a good idea, I had this set up on my 30' RV elec at the tank and mech at the the motor. At some point the elec created a blockage and was staving the mechanical pump. I removed the elec and the problem went away. I say less electrical the better, easier to trouble shoot and get fixed in a bind.
Title:
Post by: beerjet on June 01, 2010, 10:15:04 AM: Quote
I say less electrical the better, easier to trouble shoot and get fixed in a bind.
That is my thinking .
Then again , I'm borderline retarded...

-beerjet-
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 01, 2010, 11:54:57 AM: Running both might be a good idea if you were running a blown/injected alcohol deal. Even then, I'm told twin electrics are the shizzle. One as a transfer from the main tanks to the reservior tank. On a lake boat? Personally, spend the buck and a quarter or so on a Clay Smith mechanical and be done with it.

I'd do it on the Sewer Pickle, but the mechanical eccentric drive was never installed when the engine was built making going back a lil more tedious........ :screwy:

Ray
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 01, 2010, 11:56:41 AM: running electric on my new deal...hope i like it! runs 12 psi @ 160gph :screwy:
Title: Re: Mechanical convert-electrical fuel pump
Post by: Luckie Stiff on June 01, 2010, 12:00:28 PM: Quote from: Nordie on June 01, 2010, 11:56:41 AM
running electric on my new deal...hope i like it! runs 12 psi @ 160gph :screwy:

Nordie, you realize you WILL need a pressure regulator, don't you?
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 01, 2010, 12:15:02 PM: Quote from: Luckie Stiff on June 01, 2010, 12:00:28 PM
Nordie, you realize you WILL need a pressure regulator, don't you?

Nah, he dun hafta, just needs to drive faster.............to outrun the flame......... :screwy:

Ray
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 01, 2010, 12:57:24 PM: FPR with return...i am going to run the return back into the fuel water seperator....because the fuel/water seperator has 2 inlets and 2 outlets...figured that would be a good place to put it!
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 01, 2010, 01:17:24 PM: Quote from: Nordie on June 01, 2010, 12:57:24 PM
FPR with return...i am going to run the return back into the fuel water seperator....because the fuel/water seperator has 2 inlets and 2 outlets...figured that would be a good place to put it!

I don't think I'd do that lil bro. Run the returns right back to the tanks. Reason being, I think your water separators ports are for dual fuel inlets/outlets. You're gonna defeat the purpose here, not double filter the fuel.

Ray
Title: Re: Mechanical convert-electrical fuel pump
Post by: Marcsrollin on June 01, 2010, 01:37:25 PM: I run mine back to the fuel water seperator and have had zero problems with the setup.
If you have dual tanks it is the easiest way to do it.
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 01, 2010, 01:38:11 PM: why would it be a bad idea? it's just the leftover fuel not going into the carbs, and will no be running at the high pressure ::) why would i take the single line and then run it all the way back to the tank if i got somewhere i can dump it off sooner? i really dont see the big deal with this...with the filter now i can use either inlet or outlet without problem! i personally think it is absolutely simple and fool proof
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 01, 2010, 01:56:52 PM: I'm just thinking out loud, and I get it, your putting filtered fuel back in there in the mix, I'm just not sure I would do it, is all. Marc has had good luck doing it, so must be ok, I'm just over cautious and over thinking things.

In a way, thinking about it, seems like a constant filtration, but I would be concerned about reintroducing water or contaminents to the tank plumbed that way. Seems to me a whirlpool effect in the separator pumping fuel back in the filtered fuel side. Just me maybe. Should be fine, just not optimal, IMHO.

Ray
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 01, 2010, 02:04:15 PM: your still over thinking it!!!!! fuel will be coming out of seperator, and going to regulator where it will be directed to the front and rear bowl, and the leftover besides running a ton of line back to the tank you just dump it back into the fuel filter because you have a provision there to do it...it has nothing to due with double filtering or anything like that! you will have 2 inlets, and only one outlet!
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 01, 2010, 02:19:50 PM: Quote from: Nordie on June 01, 2010, 02:04:15 PM
your still over thinking it!!!!! fuel will be coming out of seperator, and going to regulator where it will be directed to the front and rear bowl, and the leftover besides running a ton of line back to the tank you just dump it back into the fuel filter because you have a provision there to do it...it has nothing to due with double filtering or anything like that! you will have 2 inlets, and only one outlet!

Yeah, I'm over thinking it. You're right lil bro, BUT, think about this. Both inbound lines will, under pressure, be drawing from the tanks indescriminately. The outbound line going to the carb/FI, is fine, the return line dumping same fuel back in. Where I think we fail to communicate is, WHERE does the return pressure go? Without a return line, it goes BACK into the system, so wheres the excess pressure and fuel go? This is where the back pressure of the electric causes issues to me.

Ray
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 01, 2010, 02:45:32 PM: the fuel filter is plenty more capable then the maybe 20psi that will be thrown at it...the whole idea is to keep the fuel moving! as to where it would not be as good if you are just running no return where the fuel is somewhat forced to stop
Title: Re: Mechanical convert-electrical fuel pump
Post by: btnhtillidie on June 03, 2010, 02:59:03 AM: I'm actually going to do the oppsite. Electric Pump over to Mech. One thing you have to remember about Eletric pumps, They were made to push fuel better than pull it. Mech on the other hand are much better at sucking. The problem I was having was the pump could not keep up with the motor. It wouldnt suck the fuel fast enough. I watched the fuel pressure drop from 5 1/2 to about 3 at 4K or above.
Title: Re: Mechanical convert-electrical fuel pump
Post by: tryklon on June 03, 2010, 08:56:44 PM: Hey gurus,

Bought the Holly blue electric marine elec fuel pump with regulator, what is the proper PSI and GPH for a stock 455?
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 03, 2010, 09:14:05 PM: i would say around 5 1/2 - 6 psi with a 4 bbl carb
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 03, 2010, 09:31:53 PM: i had to look back on this thread just to remember what i typed! hello beer!
Title: Re: Mechanical convert-electrical fuel pump
Post by: sandeggo on June 04, 2010, 08:00:34 AM: to the OP, you did prime it first right? manually pour some gas into the top of the carb so the engine runs for a bit. it gets the suction of the pump working.
Title: Re: Mechanical convert-electrical fuel pump
Post by: ROMPERSTOMPER on June 04, 2010, 02:01:01 PM: Quote from: Nordie on June 01, 2010, 12:57:24 PM
FPR with return...i am going to run the return back into the fuel water seperator....because the fuel/water seperator has 2 inlets and 2 outlets...figured that would be a good place to put it!

This will not work with efi. Tried it, don't work. I am running 60 psi tho. The problem is that your adding pressure to the fuel by doing this. At low rpm when your not using very much fuel most of it is returned. Returning fuel to anything but the tanks is also returning pressure.So your fuel pressure will be a lot higher and when you dial it back down and bring the rpm's up you wont have enough pressure. Your working your fuel pump more than you need to because you not relieving any pressure and will shorten its life.Also with that extra pressure going back to the line as a return it is also possible to push fuel back the other way causing a shortage of fuel. I'm very surprised that Marcsrollin dosent have any issues with that yet. Having more fuel than your burning going back to the supply line just doesn't make sense to me.
Title: Re: Mechanical convert-electrical fuel pump
Post by: IRRebel on June 04, 2010, 06:18:56 PM: Quote from: ROMPERSTOMPER on June 04, 2010, 02:01:01 PM
This will not work with efi. Tried it, don't work. I am running 60 psi tho. The problem is that your adding pressure to the fuel by doing this. At low rpm when your not using very much fuel most of it is returned. Returning fuel to anything but the tanks is also returning pressure.So your fuel pressure will be a lot higher and when you dial it back down and bring the rpm's up you wont have enough pressure. Your working your fuel pump more than you need to because you not relieving any pressure and will shorten its life.Also with that extra pressure going back to the line as a return it is also possible to push fuel back the other way causing a shortage of fuel. I'm very surprised that Marcsrollin dosent have any issues with that yet. Having more fuel than your burning going back to the supply line just doesn't make sense to me.

;D
Title: Re: Mechanical convert-electrical fuel pump
Post by: DTeem on June 05, 2010, 08:36:12 PM: I'm a little late getting in here but...Mine did the same thing this spring. I had replaced the filter and added a water separator. Turned over a few times and no fuel. None in the filter and none in the lines. I added some fuel to the carb with a squirt bottle and turned it over a few times until it fired up. After about three or four rotations of adding fuel until it died again I noticed fuel in the filter. Mechanic friend told me that I was on the right track cause the mechanical fuel pump had to be turned over longer to get it to pick up when the lines were completly empty. I had thought I was going to have to change out the pump but all seems to be working fine now. Will probably go with an electric eventually but...,.
Dave
Title: Re: Mechanical convert-electrical fuel pump
Post by: sandeggo on June 06, 2010, 09:03:31 AM: Quote from: DTeem on June 05, 2010, 08:36:12 PM
I'm a little late getting in here but...Mine did the same thing this spring. I had replaced the filter and added a water separator. Turned over a few times and no fuel. None in the filter and none in the lines. I added some fuel to the carb with a squirt bottle and turned it over a few times until it fired up. After about three or four rotations of adding fuel until it died again I noticed fuel in the filter. Mechanic friend told me that I was on the right track cause the mechanical fuel pump had to be turned over longer to get it to pick up when the lines were completly empty. I had thought I was going to have to change out the pump but all seems to be working fine now. Will probably go with an electric eventually but...,.
Dave
i love my mechanical. you have to prime them when you run empty. to me its no biggie.
Title: Re: Mechanical convert-electrical fuel pump
Post by: Marcsrollin on June 06, 2010, 11:18:11 AM: Quote from: ROMPERSTOMPER on June 04, 2010, 02:01:01 PM
I'm very surprised that Marcsrollin dosent have any issues with that yet. Having more fuel than your burning going back to the supply line just doesn't make sense to me.

I am not running 60 PSI!! My pump puts out 18 PSI and there is no problems what so ever! I know lots of people who do it this way , just go to a NJBA drag race and look around.
Title: Re: Mechanical convert-electrical fuel pump
Post by: Nordie on June 06, 2010, 11:45:47 AM: i be running 12 psi and after the reg aroung 6-7 psi! i really dont see there being a problem :thumbup: