TLDI 90 2002 A2 Primer bulb goes soft very quickly when engine stops

gazzagary

Cadet
Joined
Sep 1, 2007
Messages
17
Hi I was having problems with the bulb going soft and suspect an air leak somewhere. I purchased a brand new remote tank and a further genuine tohatsu fuel lead but still the same problem? the engine only starts when the bulb is really firm too which is a change in performance . when drift fishing and stopping for say five minutes I have to re prime before she starts as the bulb is soft again.. I wonder where I should start to look and check? and how do i spot an air leak as no fuel is leaking out ? The diagnosis is showing no faults and she has between 150 to 250 hours indicated by the self diagnosis. All advice welcome please,

Thanks Gary
 

pvanv

Admiral
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Apr 20, 2008
Messages
6,500
The fuel line is under suction, so the only time you would expect a truly hard primer bulb is right after you prime the motor. The bulb has 2 check valves, and if the outlet of the bulb is up, those valves will seat easier, retaining fuel in the line better. If the bulb sucks flat, that would indicate lack of available fuel, either because of a restriction between the bulb and the gas supply, or a stuck or closed vent.

The primer supplies fuel on the low pressure side of the system, and the fuel must pass through the low pressure fuel filter, the low pressure fuel pump, the vapor separator, high pressure fuel feed pump, and high pressure filter. Has the motor been stored correctly over the last decade and a half? When was the last time the vapor separator was drained? Was the separator drained for storage last winter? What size and age is your starting battery?
 

gazzagary

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Sep 1, 2007
Messages
17
Thanks Paul

Battery is no problem i believe , it is linked to two new 1000 cca and no low voltage reported. To be honest I can not recall the last time the vapour separator was drained. The engine is used and or at least started throughout the whole year. I will start with draining the water separator then it has to be a couple of years since I did that. I have changed the high pressure filter twice in its life. It might sound silly but what impact would draining the vapour separator hope to achieve please?

Many thanks
 

pvanv

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Apr 20, 2008
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crud accumulates in the vapor separator, and can get recycled through the system.
 

gazzagary

Cadet
Joined
Sep 1, 2007
Messages
17
HI I have drained the vapor seperator and still have the same problems. When I stop the engine within a few minutes the ball goes soft. I have tried three different fuel lines and two remote tanks. when you turn the key to the start position you get the buzzer beeb and I can hear the fuel pump initializing. the engine only starts when the bulb is super hard. Can the fuel pump become less effective over the years? its almost as if its not doing its job and has to be manually primed to the limit?

Also I have noticed that the bulb goes soft very quickly after the engine has stopped. I have tried disconecting at the remote tank end and it stays harder. Any ideas please?

No faults are listed on the diagnostic.
 

Sea Rider

Supreme Mariner
Joined
Sep 20, 2008
Messages
12,345
As long there's a unrestricted fuel flow from tank to fuel pump doesn't matter if bulb has turned less firm during OB use. Find that bulbs only stays firm when primmed, other that that stays less firm when OB runs or it's at stop.

Is it possible to conduct a fuel pump pressure test ? Probably fuel pump it's on its way to become kaput..

Happy Boating
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
The FFP produces nearly 100 psi, so priming the bulb doesn't even get a tenth of that to the motor. When you turn on the key and hear the ffp for a couple of seconds, that is your fuel system coming up to pressure. The priming bulb has nothing to do with it. It is not going to stay hard when running. The TLDI is not particularly friendly to the shade tree mechanic. If you are unable to diagnose it with the help of the onboard diagnostics, and there is nothing obvious, you should seek the help of your local dealer.
 
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