help please. outboard cutting out

[arkamelis]

Hi
So got boat to exmouth this week end, and to start off it was promising, launched boat, opened it up and it pretty much flew into life, so got round the corner to the marina and moored up and sorted trailer out, bit later took boat for a spin and again was blown away with just how fast it was until it started to cut out, i know it wasn't fuel as i just put £50 in, wasn't the two stroke oil plenty of that, so started it up again which took a few turns but got it going by using the throttle. so again speeded up gradually and again once it started to speed up and about to get on the plane it cut out again, i noticed the primer bulb was completely sucked in, so i waited a while and it gained its shape after 5min, started up again and managed to get back by going slowly.( no issues going slow.
Next day took it out again and same thing just kept cutting out, when reaching around 2000-2300 rev, in the end i took the primer bulb off and and just connected direct to the fitting in bulkhead thinking it was the primer bulb, sadly it did the same kept cutting out. i don't seem to get issues starting it and not much issues going slow(but did cut out occasionally going slow to )
wanted to see if anyone may have some ideas to whats wrong

[willk]

Are you using plastic tanks? If so - was the vent open?

[arkamelis]

spoke to Someone in the marina who had a similar problem and suggested it could be a air issue or vent issue, my tank is a fixed tank which doesn't have a adjustable air vent screw, but it does have a fixed pipe which goes to a fitting on the outside of the boat, i believe it to be a fire corse valve, which i guess also acts as a air intake if needed, i did also try while out testing different thing i removed to fuel tank filler cap, and no difference, still cutting out

[arkamelis]

Originally Posted by willk

Are you using plastic tanks? If so - was the vent open?

hi there . no the tank is a fixed tank

[arkamelis]

just wanted to add i do have a fuel filter

[Fenlander]

In a way the primer bulb was a good clue to your problem which could either be a venting issue as Willk says... or a blockage on the tank side of the primer bulb.

If not a venting issue could the pickup pipe be blocked... might there be a blocked pickup filter... could the pickup be touching the bottom of the tank so blocking... could any of the fuel piping from tank to bulb have internally collapsed???

Just a few random thoughts. Checking it all through from bulb to tank should get to the answer.

BTW... Before you took it off did the primer behave normally when priming?

[Xk59D]

use a 25 litre tank and see what happens, i suspect it will run fine for about 35-45 mins until you run it out of fuel

[arkamelis]

Originally Posted by Fenlander

In a way the primer bulb was a good clue to your problem which could either be a venting issue as Willk says... or a blockage on the tank side of the primer bulb.

If not a venting issue could the pickup pipe be blocked... might there be a blocked pickup filter... could the pickup be touching the bottom of the tank so blocking... could any of the fuel piping from tank to bulb have internally collapsed???

Just a few random thoughts. Checking it all through from bulb to tank should get to the answer.

BTW... Before you took it off did the primer behave normally when priming?

hi finlander
i have got the boat back home now, and i will for sure go through all you have suggested, starting from the tank, the pick up, filters and all pipes. like you both say it could be down to venting problem. i have also now had someone suggest that it could be the fuel pump and that inside it has rubber diafram things at are suppose to work together sucking in fuel and releasing. if these go you end it with it just constantly sucking in fuel but not breathing

[arkamelis]

Originally Posted by Xk59D

use a 25 litre tank and see what happens, i suspect it will run fine for about 35-45 mins until you run it out of fuel

something so simple but yet would have solved it in ten minutes, shame the boats back home now

[Davie]

On the top of fuel tank there is a brass tail that your fuel hose is connected to. On Bayliners this is a non return valve. Replace this with one without The one way valve.

[Last Tango]

Originally Posted by Davie

On the top of fuel tank there is a brass tail that your fuel hose is connected to. On Bayliners this is a non return valve. Replace this with one without The one way valve.

+1.

I've seen exactly this fault before on a Bayliner. From memory we just dismantled the valve and threw the ball and spring in the bin.

The other thing to check is the fuel cap. some of them have "one way" venting built into them. (PIA) but the filler is in quite a vulnerable location on some Bayliners so if it's faulty you'll have to replace it with the right thing.

[arkamelis]

Hi guys, thank you very much

[Last Tango]

That vent looks perilously close to the water. Is it not taking spray from the engine?

Re the filter.....no. The one you have will also double as a water trap and it's flow rate will be much higher. (you have replaced/checked it....that could be your culprit.)

As Xk59D said, the easy way to check this is to try the engine with an outboard tank. I'm sure you could bum a loan from someone.

[jeffstevens763@g]

Fuel lines collapsing, disintegrated ?

[arkamelis]

Hi guys
been looking at boat most of the day and fuel tank/pipes
Last tango
yes the vent is quite low and i did think that water could be getting in, but i have inspected it today and the pipe that joins on the inside goes up to almost the same hight has the fuel filler cap, plus i also inspected the pipe at the fuel tank end, i took it off and theres a powder around the joint ( not salt ) no signs of it being wet. while off i also blow down it to check air flow and it was fine, i could hear the air coming out the vent.

Davie
i also took apart the elbow on the fuel tank for the fuel outlet as there was concerns it was a oneway valve, turned out its not. its a straight run down the pick up pipe. before i took it out i took the hose off first and blew down the end coming out of the elbow, again blowing bubbles in the tank.
i then disconnected the fuel line in the bulk head and blew down it and i could here it coming out in the fuel tank aswell, i could also see fuel vapour coming out the vent.
i re connected every thing, apart from the fuel line from the outboard to the primer bulb, it was taking some time for fuel to come up, and i managed to get fuel coming out from the primer bulb by placing a finger over the end to get some vacuum,eventually fuel was coming out, but had to work at it.

anyway the plot thickens, reconnected fuel line from outboard to primer bulb and squeezed till it filled with fuel, i could also see fuel movement in the small fuel filter inside the outboard. i got the outboard started and used throttle to get it going then backed off and let it run so i could flush outboard, after about three minutes i could here it starting to slug a bit, so i squeezed the primer which was already full of fuel and it seemed to pick up a little, but eventually cut out, and i carnt get it to start again now, just keeps turning but not fire'ing
i don't know whats going on
i was going to get a jerry can and fill it and just pop the outboard fuel line in and see if i can get it going again tomorrow, im really hoping its not knackered, ive only just brought it

[arkamelis]

most of the fuel lines are new

[arkamelis]

Originally Posted by Last Tango

That vent looks perilously close to the water. Is it not taking spray from the engine?

Re the filter.....no. The one you have will also double as a water trap and it's flow rate will be much higher. (you have replaced/checked it....that could be your culprit.)

As Xk59D said, the easy way to check this is to try the engine with an outboard tank. I'm sure you could bum a loan from someone.

i think to be on the safe side i might re-locate the vent, if at times its submerged or constant spray from outboard, i guess it is possible water could travel to fuel tank, specially if pressured from spray.
you mentioned the fuel filter, what would i be looking for ?

[Fenlander]

Not 100% sure from description but have you blown down from the primer location all the way to the tank end to check the main run isn't obviously blocked?

Remember when blowing you are not replicating the running condition which is a vacuum from the OB end. If you had a soft or kinked bit of hose that vacuum could just be enough to close it up. Similarly if there was a bit of debris half stuck at the bottom of the tank pickup pipe you might be blowing it away slightly to get bubbles... but in the running condition the debris could be gradually sucked to the pickup to block it.

Agree with Xk59D upthread.... getting a normal tank... or anything you can make up to fuel the OB directly... to prove the OB is OK will head you in the right direction.

[Striker]

Originally Posted by arkamelis

Hi guys

been looking at boat most of the day and fuel tank/pipes

Last tango

yes the vent is quite low and i did think that water could be getting in, but i have inspected it today and the pipe that joins on the inside goes up to almost the same hight has the fuel filler cap, plus i also inspected the pipe at the fuel tank end, i took it off and theres a powder around the joint ( not salt ) no signs of it being wet. while off i also blow down it to check air flow and it was fine, i could hear the air coming out the vent.



Davie

i also took apart the elbow on the fuel tank for the fuel outlet as there was concerns it was a oneway valve, turned out its not. its a straight run down the pick up pipe. before i took it out i took the hose off first and blew down the end coming out of the elbow, again blowing bubbles in the tank.

i then disconnected the fuel line in the bulk head and blew down it and i could here it coming out in the fuel tank aswell, i could also see fuel vapour coming out the vent.

i re connected every thing, apart from the fuel line from the outboard to the primer bulb, it was taking some time for fuel to come up, and i managed to get fuel coming out from the primer bulb by placing a finger over the end to get some vacuum,eventually fuel was coming out, but had to work at it.



anyway the plot thickens, reconnected fuel line from outboard to primer bulb and squeezed till it filled with fuel, i could also see fuel movement in the small fuel filter inside the outboard. i got the outboard started and used throttle to get it going then backed off and let it run so i could flush outboard, after about three minutes i could here it starting to slug a bit, so i squeezed the primer which was already full of fuel and it seemed to pick up a little, but eventually cut out, and i carnt get it to start again now, just keeps turning but not fire'ing

i don't know whats going on

i was going to get a jerry can and fill it and just pop the outboard fuel line in and see if i can get it going again tomorrow, im really hoping its not knackered, ive only just brought it

You could have loose debris in the tank that gets drawn to the pickup when running and falls away again when stopped, particularly if you have blown back down it.

I once took hours to find a fault on a double decker bus that turned out to be a dead bee in the tank.

It might be worth taking the fuel level sender unit out and having a look inside. You would be sure about you vent drawing water in at the same time.

I wouldn’t be worried about the outboard at this stage, it’s simply not getting enough fuel to cope when under load.

And renew your filter as a priority it’s usually the simplest thing. I would do this before anything else.

We had a spate of cars breaking down that could all be traced back to having filled up at a local Tesco. Their fuel was contaminated with a very fine chalky powder that was clogging filters. It couldn’t be seen when wet but when I cut open a filter and let it dry overnight the substance was flaking of the paper. If you suspect the fuel is dodgy drain it and replace it.

[jeffstevens763@g]

fuel pump?