Primer bulb query

hobnob · 28 July 2008, 11:55

Hello,

Went playing with my SIB yesterday on the Thames. It has a 8hp 2T engine from 2003, and a Yamaha original parts fuel line and 13l tank.

I squeezed the primer bulb for ages (30 times) and it did not get hard as per normal. It remained soft although I could hear fuel flow. Wife then said I was 'faffing' so I got impatient and yanked the starter. Engine started fine so away we went!

After a sojourn at 'Steins' in Richmond, I tried to re-prime the engine but this time the bulb was hard! Engine starts fine again.

Inspected the engine after the trip; there are no fuel leaks and the spark plugs suggest mixture is good (they're a light dusty brown).

Should I assume the primer bulb is questionable, and replace it? Anything else to check? Could the engine fuel system be to blame? Operator error?

TIA,

hobnob

jyasaki · 28 July 2008, 16:39

Could be the primer bulb leaking back towards the tank, could be air was in the section between engine and bulb, could be a leak between engine and bulb. Probably a few others I'm not thinking of.

If it ran OK, and you don't have to reprime for a few hours after running, I wouldn't worry too much.

FWIW, I rarely had to prime my Honda 40; almost never have to prime the F115.

jky

Chris · 28 July 2008, 20:04

I find that a primer bulb is only really happy when it is more vertical and pumping uphill and not down.

If I try to pump mine when it is hanging down it doesn't get hard.

matt h · 28 July 2008, 20:15

i always pump mine when down, and the other day it got so hard it blew up!! sometimes i get my missus to pump it for me, she loves pumping it,especially when it gets really hard, most of the time when it gets so hard, she cant put her hand around it,!!!!

nikster · 28 July 2008, 22:00

hobs... common problem in this kind of weather for some - quick fix is to depress the ball on the engine connector end and squeeze primer to get the vacuum out, it will only take 1 or 2 squeeze then the fuel will come through / spit at you - it is the same as the engine drawing it through when running.....

You can sit there for ages trying to pump a limp primer - but it actually needs fresh air pulling through to start the process..... :-) doesnt sound like a replacement to me....!

Hightower · 28 July 2008, 22:43

Two weekends ago I was doing some slow motoring down a creek when the engine spluttered and came to a halt, after a few attempts at failing to start it I checked the fuel Primer bulb which was soft, now I never need to prime the fuel system from one trip to another, but thought I'd give a few pumps till hard, after a futher 4 attepts the engine started and ran fine for the rest of the day.

Was this coincidentle or were the plugs oiled up.....One will never know, but! Has anyone else had this happen to them?

m chappelow · 28 July 2008, 23:44

it can also depend if the fuel tank air vent has been closed on a hot day when the fuel line is connected the presure in the tank can just about prime the engine sometimes ,also the ball valves in the bulbs can leak fuel back down the line at slow speeds . and as some one earlier just said they can get air locked at times if the pipe is empty ,they are designed to pump fluids better than air.

hobnob · 29 July 2008, 10:37

Thanks for all the replies. I will blame an air lock for the problem. Are there any pills for the fuel system that can help?..

Nos4r2 · 29 July 2008, 10:49

Quote:

Originally Posted by hobnob

Thanks for all the replies. I will blame an air lock for the problem. Are there any pills for the fuel system that can help?..

If you've had a problem with the bulb like that it's worth carrying a spare.

ribpilot · 29 July 2008, 16:09

Quote:

Originally Posted by matt h

i always pump mine when down, and the other day it got so hard it blew up!! sometimes i get my missus to pump it for me, she loves pumping it,especially when it gets really hard, most of the time when it gets so hard, she cant put her hand around it,!!!!

I just fell off my chair laughing