Bosch inline fuel pumps

[AndyStobbs]

Hello gents, some of you I know are into performance cars and modding etc.

I would like to add an electric fuel pump to my jetski - or at least buy one suitable so I have it at hand should I need it.
The carbs on my ski have a built in pump section, which has been trouble from day one. I rebuilt the carbs before first use last year but I fear the parts were inferior, I hit a wall sourcing genuine mikuni and so had to go with WSM - a well known brand in the jetski market.

The fuel pump section is pulse driven using manifold pressure changes, two plastic valves form the working parts, it was never right, but I found it far better if I doubled up the plastic discs and the ski has ran well all of last year with that in place.
Anyway I've been looking at fuel pumps, particularly Bosch Number 0580464070,
but given how it looks, it would appear to need to be flooded suction, can anyone confirm?

The two fuel pick up tubes are in the top of the tank, utilising two different length dip tubes to give main and reserve modes. Then they rise about 12" to the fuel tap.
So all in, the pump would have a lot of pipe to prime.

Thanks

 

[711jrp]

Mikuni do a remote mount pulse pump, running one or two of these was the hot ticket, even better when coupled with a vapor separator such as the Novi one. I did mess with electric pumps but made the carbs a nightmare to tune as it messes with the pop-off pressure.

 

[Jim Davey]

I was going to say the same, most early skis had a separate pump you just needed to run a pipe to the crank case.
Electric pumps are all likely to give too much pressure.

 

[Pete.]

The Bosch 058 is a high pressure pump for fuel injection. They do a low pressure pump for carbs but I don't know the number.

 

[bill_gj]

That part number is typically intended for a 5 bar injection system and will just flood the whole fuel system when connected to 12V.
It is a 60mm diameter Bosch pump and their pumps of that diameter start at a specified 120 litre/hour at 5 bar and rise to over 150 litre/hour at 5.8 bar.
These are Bosch's typical specifications and, from my own experience, they are minimum flows. They were originally designed for theK-Jetronic systems.

The similar looking 52mm dia pumps are generally 130 litre/hr at 3 bar, so will also be far too much flow capability (eg: 0580464070). These were designed for the L-Jetronic systems.

As you mentioned, these pump packages generally need to have a flooded inlet to make sure there is no restriction and so cavitation at the inlet.

For a carb system, unless it's to feed a humongous gas-guzzler, you'd be better off with a solenoid-type pump, like this:
http://www.amazon.com/Delphi-FD0031-Electric-Motor-Solenoid/dp/B000CGJWZQ
Quite a few about.

You could use a big Bosch pump and power it via a PWM unit and turn the wick right down.
http://www.amazon.com/12V-24V-Contr...qid=1457901729&sr=1-6&keywords=pwm+controller

 

[AndyStobbs]

Mikuni do a remote mount pulse pump, running one or two of these was the hot ticket, even better when coupled with a vapor separator such as the Novi one. I did mess with electric pumps but made the carbs a nightmare to tune as it messes with the pop-off pressure.

I was concerned about the pop off angle, what I really need is flow at minimal pressure. The bosch pump is 3bar nominal - quite a bit above my 16psi pop off.
I have seen the separate pump mentioned in the service manual on the 1000cc model ski.
Is it common for the square block carbs to give fuel pump problems?

Also on a side issue, if you plant the throttle from idle the engine will die, carbs are Bn38's, pop off is absolutely correct at the book figure of 16psi, and all bypass holes and jets, and carb internals are perfectly clean. Was planning to play with the slow running jet size but its such a fag. Would you advise going lower on pop off (seems very low already)?
The ski runs great with gentle application of throttle and once off idle the throttle can be applied ruthlessly without any problem.

Most of the above aimed at you 711jrp, thanks.

 

[AndyStobbs]

That part number is typically intended for a 5 bar injection system and will just flood the whole fuel system when connected to 12V.
It is a 60mm diameter Bosch pump and their pumps of that diameter start at a specified 120 litre/hour at 5 bar and rise to over 150 litre/hour at 5.8 bar.
These are Bosch's typical specifications and, from my own experience, they are minimum flows. They were originally designed for theK-Jetronic systems.

The similar looking 52mm dia pumps are generally 130 litre/hr at 3 bar, so will also be far too much flow capability (eg: 0580464070). These were designed for the L-Jetronic systems.

As you mentioned, these pump packages generally need to have a flooded inlet to make sure there is no restriction and so cavitation at the inlet.

For a carb system, unless it's to feed a humongous gas-guzzler, you'd be better off with a solenoid-type pump, like this:
http://www.amazon.com/Delphi-FD0031-Electric-Motor-Solenoid/dp/B000CGJWZQ
Quite a few about.

You could use a big Bosch pump and power it via a PWM unit and turn the wick right down.
http://www.amazon.com/12V-24V-Contr...qid=1457901729&sr=1-6&keywords=pwm+controller

Thanks, will ask my motor factors about the Delphi, see if they can get one.

 

[Jim Davey]

Are you on PWC forum Andy? Lots of help on there.

 

[AndyStobbs]

I'm not, I, really can't be bothered with forums, except this one. Too much bad information on most of them. Every now and then a specialist forum turns up a golden nugget of information, but only after I've waded through 5 pages worth of jargon.

 

[Cobbler]

Facet due a range of electric fuel pumps for inline use, bit like a modern replacement for an SU pump for use with carbs. Look at Merlin motor sport, there are different output pressures to suit various applications

 

[Jim Davey]

Or try Think Automotive Isleworth.

PWC is good, lots of knowledge there.

 

[711jrp]

I was concerned about the pop off angle, what I really need is flow at minimal pressure. The bosch pump is 3bar nominal - quite a bit above my 16psi pop off.
I have seen the separate pump mentioned in the service manual on the 1000cc model ski.
Is it common for the square block carbs to give fuel pump problems?

Also on a side issue, if you plant the throttle from idle the engine will die, carbs are Bn38's, pop off is absolutely correct at the book figure of 16psi, and all bypass holes and jets, and carb internals are perfectly clean. Was planning to play with the slow running jet size but its such a fag. Would you advise going lower on pop off (seems very low already)?
The ski runs great with gentle application of throttle and once off idle the throttle can be applied ruthlessly without any problem.

Most of the above aimed at you 711jrp, thanks.

I used to use N@C for parts over here, this is the pump I was talking about. When you say she dies when you crack it open....does she stutter and die or just bog down without the stutter? if that makes sense

 

[AndyStobbs]

Bogs down, like the ignition was cut off. No attempt made to pick up at all.

 

[711jrp]

First I would say that pop-off was to low, I like 20-ish and the bike is too rich. I would close up the low speed screw as my first port of call but I would find out where it is first by slowly tightening it and making note of how many revolutions it takes to close

 

[AndyStobbs]

Adjustments of low speed screw has absolutely no affect on the issue. From 3/4 turn to 3 turns the ski will idle, and the problem doesn't change at all. On about 1 3/4 turns out at the moment, seems to give a nice smooth idle and reliable hot / cold starting.

 

[AndyStobbs]

Increasing the pop off will lean out the mixture, yes? You think its overly rich then?

 

[711jrp]

Yes I'm sure it's overly rich and yes increasing to pop-off will lean it out but I actually think the problem might be the low speed adjuster (screw) is set to rich to compensate for the low pop-off.I would try leaning that out first as it's easy to do. Have you seen Group K site they have some very good info to read up on. what bike is it?

 

[AndyStobbs]

Its a tigershark 770. I should add, when its out of water it will rev up cleanly, but of course without the drag it idles much higher to start with.

 

[711jrp]

I thought the carb/carbs were super bn's on those, a couple of mates had them back in the day. They all run fine out the water don't they...grrrrr

 

[AndyStobbs]

I thought the carb/carbs were super bn's on those, a couple of mates had them back in the day. They all run fine out the water don't they...grrrrr

Sorry I omitted the Super from the earlier post, they are Sbn38's. Later skis got the 38i with accel pump - I want a set lol