Engine "sneeze"

mattiasb · 18 August 2003, 10:22

Hi,
I experience problems with my Johnson V6 175 hp. It's running bad to dead in low revs and idling. It's supposed to be water in the gas but I've drained the carburators and several times emtied the petrol filter. The engine continues to "sneeze" at low revs and finally die.

Any mechanic out there who could give me a good advice I'd be grateful.

Many thanks

/Matt -Sweden

-<=[Tw18]=>- · 18 August 2003, 10:30

I've just been to my machanic's after this started since they put in new plugs. And they told me exactly the same. Dirty fuel, water in fuel. Check the plug cap's etc. But it has only been since they put the new plugs in. And 'sneezing' would describe it perfectly. So any help will be gratefully accepted.

Lee

Charles · 18 August 2003, 11:31

Take two ColdCaps, go to bed with some tissues and have a rest - Muahaha

Pete7 · 18 August 2003, 12:12

Used to have a Yamaha that did this once in a while, at tickover. Turned out to be a slightly bent read valve that occasionally didn't seat properly and allowed the fuel air mix back out. The reeds on a carb engine are behind the carbs which can normally be removed in one. The reeds look like petals and are very thin strips of metal. Could be that a bit of dirt or gum/varnish from old petrol as stuck one open slightly. If you don't want to take the carbs off, try a can of Quicksilver carb cleaner in the engine whilst its running, might solve the trick, either way its a DIY job before you have to start paying a mechanic.

Pete

Cookee · 18 August 2003, 19:31

It's no good draining the carbs if there is still water in the tank - you'll just collect more water in the carbs - you should be able to see if there is water in there when you strip them.

Also get yourself a water seperating filter, that way it will limit your chances of the problem recurring (remember to drain off any water reguarly!) - assuming that's what it was to start with!

mattiasb · 19 August 2003, 06:48

I know, the problem is that I have a water separating filter and I empty this often. I'm starting to think the water get's in after the filter? Again assuming water is the prblem.

/Matt

jwalker · 19 August 2003, 15:52

Weak idling mixture can give this effect. It normally stops on the 'sneeze'.

-<=[Tw18]=>- · 19 August 2003, 19:32

Right I am hoping someone can help please.

Attached is a picture of my fuel filter, sorry about the quality but the pics where taken with my mobile which was all i had on me when I just went down to check the boat.

The top picture shows the underside of the filter. There is this twist in plug. When under slightly undone it lets the contents of the bottom of the filter drain out.

Now should with this model I drain out the bottom area which is liquid. Or do i replace the whole unit??

Thank You
Lee

Jizm · 20 August 2003, 02:49

I had this problem on my engine. I renewed the fuel and filters but that made no difference. I referred to the manual which stated the pilot screw base settings on the carbs and set them as specified. Problem cured, seems to start more easily and rev more cleanly aswell.
regards
jizm

Pete7 · 20 August 2003, 07:22

Lee that looks like a standard diesel filter. No problem there, as they are finer filters than petrol engines and despite the manufacturers saying you shouldn't, I have used them with petrol engines for years.

The cartridges are about £3 from an accessory shop. The 296 is the finest and 522 slightly courser but both will work fine and at that price not worth messing about with. Buy two and carry the spare on board.

Pete

-<=[Tw18]=>- · 20 August 2003, 09:05

thanx pete, all i have to do now is fine someone o sell me one

Bilge Rat · 20 August 2003, 09:25

Hi

I had a strange experience a few weeks ago on my boat, engine kept dying when running at top speed, strange i thought maybe it has something to do with the fuel, so i swapped the fuel lines over to my spare plastic tank on the deck and the boat ran fine, after a while i changed back again to the stainless tank and the same problem re occured, luckily i was out on the water with my mechanical friend who jigged about and checked the engine over and came to the conclussion it was either the fuel line itself or the sender in the tank, we popped into the beach and i went and found a chandlers and replaced the entire fuel line and bulb with new and suprise suprise this fixed the problem....After checking the old line i could see absolutely nothing wrong with it, i even took as much of the bulb apart as i could to have a look.
All very strange stuff, how can something that looks like its working fine with no moving parts be playing up.

R

mattiasb · 20 August 2003, 09:50

Great,
This is my next move, I'll replace the fuel-line and bubble. It runs under-deck which makes inspection harder, also the fuel-filter is located before this line, not aft close to engine - wouldn't that be smarter.

Thankyou all dedicated and helpful Rib-people out there!

PS. Anyone with a twin-engined 7 m Rib with lots of equipment, no more than 5 yrs old up for sale? Drop me an e-mail. DS

/Matt

Pete7 · 20 August 2003, 10:10

Lee, any car accessory shop should sell them, if not a truck dealer like a ford garage. The expensive option is the local volvo penta marine dealer or chandlers. They are very common filters.

Matt, don't think the location of the filter makes much difference, better to chose somewhere it won't be damaged, is easy to check, drain/clean and won't corrode (and if you find such a location on a rib let us know cos its like a holy grail)

Pete

Bilge Rat · 20 August 2003, 10:18

Matt

An inline fuel filter is on my list of things to do very soon, it will be located on the transom and the fuel bulb located in the line between the filter and the engine, this way i can have a quick connector to each tank and just swop them over, was planning to fit a valve but i've been advised this causes all sorts of air problems and its best to keep everything simple.

Not sure if swopping out the fuel line will solve your problems, i thought when i was told it was the fuel line that he was joking but as the tank had just been cleaned out inside and is as good as new there couldn't be anything wrong with it, we proved the engine ran fine at full revs on a seperate auxillary tank so it had to be either the fuel line or the sender, the fuel line and bulb cost me £12 to replace and got me going again quickly, give it a try might be worth your while changing it out if its old anyway.
I'd suggest though before pulling the old line out and pulling new line through the conduit you just run the new line over the deck (if thats possible) and connect it up temporarily at each end and see if this solves the problem, if it does you can make it look pretty at your leisure, if not then you've not gone to the trouble of running new fuel line under the deck and just have a seperate spare bit of pipe for future use.

Hey have found with boats its normally the simplest things that go wrong, dodgy impellor put me off the water for 3 weeks 2 weeks ago !!! no obvious damage to it on inspection and it felt ok to the touch, just shows you doesn't it.

Richard

-<=[Tw18]=>- · 20 August 2003, 11:46

Quote:

Originally posted by Pete7
Lee, any car accessory shop should sell them, if not a truck dealer like a ford garage. The expensive option is the local volvo penta marine dealer or chandlers. They are very common filters.

Matt, don't think the location of the filter makes much difference, better to chose somewhere it won't be damaged, is easy to check, drain/clean and won't corrode (and if you find such a location on a rib let us know cos its like a holy grail)

Pete

OK i suppose the difference between a fuel filter and, water / fuel seperator are self explainitory, but what is mine?

Would any car shop stock teh later?

Sorry

Lee

Bilge Rat · 20 August 2003, 14:34

Guys on the subject of fuel filters/water seperators.

Someone correct me but does the petrol float to the top of the filter chamber and the outlet to the engine will be at the top.
Its been recommeded to me to buy a clear glass type filter jar, apparently this way you can see the water collect at the bottom of the jar and remove it periodically. Off course any new filter is in addition to the inline filter inside the engine cover and is meant as an additional barrier to dirty and water ingress or can one just remove the inline filter and run a pipe straight through ?

Richard

-<=[Tw18]=>- · 20 August 2003, 14:42

Ok, I applogise

There is me asking if it was a fuel water seporator or a fuel filter. When all I had to do was read it
FRAM C1191PL FUEL FILTER

i am sorry for my stupidity I shall sit in the corner £3.60 each

Richard B · 20 August 2003, 14:53

That unit you've posted the picture of is both a filter and a separator.

The cartridge being the filter, and the lower unit (glass bit underneath) is the separator. The heavier water sinks down into the separator, and you can drain it off.

Mr Bilge Rat - that's exactly what you need.

-<=[Tw18]=>- · 20 August 2003, 14:56

Quote:

Originally posted by Richard B
That unit you've posted the picture of is both a filter and a separator.

The cartridge being the filter, and the lower unit (glass bit underneath) is the separator. The heavier water sinks down into the separator, and you can drain it off.

Mr Bilge Rat - that's exactly what you need.

Thats where i got confused!

there is a difinitive liquid line in the bottom which is clear, and top which is green (petrol)!

so tonight when I change the filter should I drain everything out of the bottom anyhow?