Before I start to strip the fuel system... - Page 2

Hightower · 25 August 2008, 23:21

Quote:

Originally Posted by spartacus

A marine engineer advised me to fit the priming bulb should be situated between the filter and the engine. Reason he gave was that this reduced the possibility of forcing through any impurities/water into the engine. Makes sense to me.

Yes, that's a valid point. One I hadn't thought of before.

Thanks very much

Chris · 27 August 2008, 19:12

My bulb goes hard when I prime, then once the engine start it goes soft, this would make sense to me as once the engine starts running it will be sucking fuel through the fuel line therby releasing the pressure in the bulb.

I never normally bother priming as the fuel lift pump in the etec does all that anyway.

Top banana · 27 August 2008, 21:05

Had a simmilar problem on my last boat. it ended up that the sealant used on the sender unit had constant contact with the fuel in the tank and had gone to jelly partially blocking the fuel line, the engine ran fine on start up and upto about 25knts and there after would die right back, cought and splutter
stop totally, and after leaving a short while would start and run , but you could allways feel it wasnt right. maybe a possibility in your case.

Hightower · 27 August 2008, 23:18

I don't have problems at high speed, all that seems fine.

It's just happened twice in recent trips at low speeds when she coughs and splutters to a stop. A quick prime and a few attempts to start and she fires into life again and runs good for the remainder of the trip. Just like to get to the bottom of it. Will have a look on Friday.

Hightower · 30 August 2008, 13:15

I've had my head in the console all morning fiddling with fuel pipes, Filter, bulb and sender unit. What I found was a little interesting.

First thing I did was strip out all the hose from the tank to the flow sender.

The first observation I made was that the fuel pickup pipe comming out the tank was made from copper and as such had deformed from the clamping force of the jubilee clip that was holding the hose on (wasn't tight when I removed it). My thoughts were a restriction in the line causing possible fuel starvation problems at WOT and air entering the system at this point.

First I tried to remove the fitting but was impossible to do so as it was filled with gel-coat

I wouldn't have minded replacing this with a stainless tube, but there is another fitting gland I could use behind, so I'll be phoning up Osprey on Monday and asking them for another compression fitting.

To reform the pipe I used a selection of drill bits from 5mm dia though to a 7.9mm one and pushed them down the hole wiggling it as I went. I then connected the hose back up between the pickup tube and filter using two jubilee clips to spead the load a little more (fingers crossed).

Next was relocating and refitting the primer bulb, I had to alter the hose tail configuration on the filter body. The filter was partly drained and blanking plug + fitting were swapped over using liquid thread sealant as I went. Then new pipe was cut to length and fitted to the primer bulb this was all connected up using jubilee clips. The other side of the primer bulb was connected to the Fuel flow sensor.

All was primed up and ran the engine giving the primer bulb a few gentle pumps to help air out of the system. I ran the outboard for 10 mins and in this time I noticed that as I pumped the primer bulb that some petrol was leaking from around one of the connectors (part of bulb). So these were replaced with jubilee clips too.

I also noticed that the fuel flow sensor had no output (was working fine before) and I hadn't even touched this part other than to remove and reconnect the hose. So this might still need some attention. I might go down to Fairweathers later and buy a spare fuel primer bulb.

So to sum up, I'll be taking her out for a run tomorrow now. The fuel flow sensor isn't working properly, but a good run might clear it.

Rigaud · 30 August 2008, 14:30

Sounds like your process of going step by step is paying off and your finding the small leaks. I did the same as posted here and for me as well it payed off to strip down to find the leaks. Got new fuel filter, water seperator and replaced one fuel line along with carb rebuild. I primed her up this morning started without the choke to idle real smood.

The only sure way to find these little pesky problems is to strip down fromone end till you resolve the issues. Keep going the way you are and you should have all back in proper running order.

Hightower · 31 August 2008, 17:31

Took her out today and all was well untill I reached that point down Wooten creek again, excact same spot as before would you believe it. A few pumps on the primer had her purring again. Unlike before I felt much more resistance in the bulb everytime I checked it.

The Fuel flow was a bit sporadic in its operation, so this needs looking at too.

I bought a quicksilver primer bulb yesterday, so will try swapping this for the BRP one that is currently one there.

jyasaki · 31 August 2008, 22:22

Quote:

Originally Posted by spartacus

A marine engineer advised me to fit the priming bulb should be situated between the filter and the engine. Reason he gave was that this reduced the possibility of forcing through any impurities/water into the engine. Makes sense to me.

Does it? Assuming everything is working, it's a closed system. Any fuel you push up towards the engine (and through the filter if it's mounted between the bulb and motor) will be replaced with fuel from the engine. Filter sees the same amount of fuel either way, and all at the same rates, so what can be safer about one over the other?

jky

yorfuoj · 31 August 2008, 22:59

Having the primer bilb soft while rinning seems normal to me, as it is hard when you apply hand pressure on it only.Then, it just leaves the fuel pass thru while pumped by the motor pump.

Do you have a quick-fit connector at engine entry ? or is the tube directly connected to the motor hose, without connector as big engine require.
I had several problems with this Yam quick connector, it is really unsafe because the rubber sticks on the metal, and if you remove the connector the rubber stays on the metal and the metal ball jumps because it is pushed away by the spring ... if you were lucky it went into the boat, not into the sea !
Now I keep one spare ...

I had more or less the same behaviour as your with a 80hp Selva LPDFI, which was stopping after 10 to 15minutes running at low speed - but perfect at rest or mid power .
I lowered the length of hose, changed the primer for another make, at the end it worked fine.
I think the pump was not powerful enough to suck enough fuel at that speed

waverunner · 01 September 2008, 18:46

Have you tried installing a portable fuel tank with a primer bulb and hose directly to your engine, this way you bypass your existing fuel setup. If you still have problems you then need to look at your engine for a fault.

Hightower · 01 September 2008, 20:57

Quote:

Originally Posted by waverunner

Have you tried installing a portable fuel tank with a primer bulb and hose directly to your engine, this way you bypass your existing fuel setup. If you still have problems you then need to look at your engine for a fault.

Used 60 litres on Sunday, that's a big tank for a trial, but I see where you're comming from.

Now I know what to do if I get the problem again it's not such a worry. I will change the Primer bulb for next weekend and see how I get on.

Rigaud · 01 September 2008, 21:47

@Hightower:

I got success finally myself from stripping down from the tank on and the last 2 days with 80 litres burnt & 60 miles so far I have an engine that starts and performs as a new one. Got almost a steady 55 plus mph with no troubles so it's worth the trouble to take the time to clean up, rebuild and or replace parts.

Hightower · 01 September 2008, 23:52

Quote:

Originally Posted by Rigaud

@Hightower:

I got success finally myself from stripping down from the tank on and the last 2 days with 80 litres burnt & 60 miles so far I have an engine that starts and performs as a new one. Got almost a steady 55 plus mph with no troubles so it's worth the trouble to take the time to clean up, rebuild and or replace parts.

Yes, I am trying to systematically to eliminate areas and to change the configuration of the hoses etc to find a solution that works. As the bulb is high on the list as a failier Items, this will be swapped over before the next voyage, then in the mean time a fitting will be ordered to fit the other gland on the fuel tank and a stainless pick up tube will be fitted. If this still doesn't work, then the filter will be replaced for one that doesn't have a clear water seperator bowl at the bottom. I'm still convinced that air is entering the system from somewhere.

Rigaud · 02 September 2008, 00:13

Quote:

Originally Posted by Hightower

Yes, I am trying to systematically to eliminate areas and to change the configuration of the hoses etc to find a solution that works. As the bulb is high on the list as a failier Items, this will be swapped over before the next voyage, then in the mean time a fitting will be ordered to fit the other gland on the fuel tank and a stainless pick up tube will be fitted. If this still doesn't work, then the filter will be replaced for one that doesn't have a clear water seperator bowl at the bottom. I'm still convinced that air is entering the system from somewhere.

My main problem this last time was my fuel filter which had a hairline crack in it but did not ever show any sign of leaking. I only found it because while still under pressure I moved the fuel line & filter, squirt, squirt came a thin stream of fuel. Replaced it along with a few lines and all seemed good. I simpatize with you because I know what it feels like to have a constant small anoying problem. It got bad on my return last weekend from a day long run with the family and limped back to the Marina.

Now since yesterday all is good for me and I wish you the same as soon as possible.

Cheers
John

Hightower · 02 September 2008, 00:18

Thanks for your kind words John.

My whole system is has less than 45 hrs on and less than a year old, so you'd expect not to find any equipement reliablility problems, but I'll keep you informed.

Rigaud · 02 September 2008, 09:47

45hrs? Wow, I agree that you shouldn't have any issues since that's concidered still new.

ribber · 19 October 2008, 15:23

Hightower have you got to the bottom of this!

Long story on my fuel problem was solved by changing primer bulb.

I then dissected the bulb and found one of the non return ball (inlet side) was sticking shut preventing the flow from tank to engine, causing the bulb to collapse and stay collapsed. Eventually the engine suction dissipated and the bulb would return to shape and would work again for a few days. Caused, I think by over tightening of jubilee clip, distorting plastic tube, hence ball getting stuck.

In your case the bulb goes soft with the engine running, perhaps the ball (inlet side) will not close when bulb squeezed, thereby you are pushing fuel back down to your tank. (Five quick squeezes of the bulb would beat the engine draw and the bulb should be firm!)

What causes your engine to stall at low revs!!!!!!!!!! Could it be the non return ball (outlet side) is sticking shut when engine is not pulling for fuel at its strongest point ie low revs. This may have been caused by over tightening of jubilee clip outlet side.

Starting to confuse myself now, but having dissected a bulb, it gives you a clearer understanding of how they work and what gives the most grief. I'm sure sticky residue in fuel and distorted orientation of bulbs cause many combinations of 'sticking balls'

Hightower · 19 October 2008, 21:00

Well I'm not sure if the problem is solved really, but I did replace the primer bulb with a quicksilver one. I also changed the position of the primer to between the filter and engine. I have also changed my starting proceedure to a few quick squeezes on the primer and haven't had a repeat of the problem since. I also have a new pickup tube at the ready, but haven't fitted it yet (thanks to Roy).

So fingers crossed.

Glad you got your's sorted.

two stroke mick · 03 January 2009, 19:10

I just fitted a tempo primer bulb to day (new out of the bag) it would not work. I also had a OMC bulb worked perfect after I dumped the new tempo one

let this be a warning. If you are keeping a spare bulb on board pray that it is not a tempo or if it is pray that you never need it.

And before you ask it was plumbed up in the correct direction

TSM

jyasaki · 04 January 2009, 02:08

Quote:

Originally Posted by two stroke mick

I just fitted a tempo primer bulb to day (new out of the bag) it would not work.

The first (and last) Tempo bulb I bought wouldn't even pump air, much less fuel. Connectors at both ends of the fuel line required alteration to work acceptably (which is not to say well), despite being listed as a direct replacement.

No more Tempo fuel line components for me.

jky