Yamaha with a flat fuel primer

[timddo]

On my last trip fishing, motor started fine but as soon as I increase the revs it starts to choke. Fuel primer is flat. Then it would engage and off she goes. Seems like fuel starvation but once revs are up she's fine. Motor seems to lug alittle Anyone with suggestions

[wiz]

Check the breather for blockage

[FNQCairns]

Yeah check for blockage at the tank somewhere like wiz says and also consider a sticky valve at the inlet to the primer, the best quality primer affordable is always a good idea.

If it where my engine (2 stroke)I wouldn't drive it again until I fixed it.

[seahound]

Suggests a blockage towards the tank from the bulb or as above - blocked breather.

I used to get this prob after a period of no use in my previous tub resulting in the engine stopping from fuel starvation. Would turn the bulb around and pump back into tank. Was some cr^p getting stuck around the pick up in the tank (underfloor job). Easy to fix but tedious

May also be as simple as a buggered bulb

[dreemon]

I was getting the same thing and thought blocked breather vent but it was fine. it still did it , " mine is a yammy too" I have 2 X 24 ltr portables , anyway it turned out to be the connector to the tank from the fuel hose, you HAVE to go genuine on this part. check to see if yours is even a tiny bit loose.

I only found out by changing tanks back and forth. beleive me I scratched my head till it bleed .:P

[Crocodile]

Hello timddo,
I have had the same problem on one of my 24l plastic tanks.
It is a genuine Yamaha tank plus fitting.
You have to be careful that the little "rod" part in the tank fitting aligns perfectly with the "ball" part on the fuel hose.
Easy enough to test at home when running on the muffs.
Good luck.

[timddo]

My motor is actually a 115 2 stroke with underfloor tank. I have two breathers running from the tank and can see gass escaping when i fill up.

The outboard would start but as soon as i put it in gear, it would lug and be stubborn, seems like misfire as the motor will shake, then a few sec's later it would take off.

Could i have done damanage to it as i towed a boat in a few months ago for about an hour. But since then have gone offshore with no problems.

I have clean the filters ( filter is 2 weeks old) and got a genuine primer pump.

I will check that yamaha plug at the front this arvo and give it a run with the hose.

[gofishin]

If the breathers are free, then it is a blockage between the pickup and the bulb inlet, not downstream. As a double check for breather blockage, open the filler cap when the bulb has compressed, & if you hear a 'whoosh' it is a blocked breather(s), but as you have two breathers it is unlikely anyway. Out of interest is your boat a Stacer? As others have suggested, first try a new primer bulb. If this doesn't work then some questions..

Is the bulb after the filter or before (re flow direction)?
Has it only happened after the filter change?
Did you mean you cleaned the filters, or put clean filters in?
And did you mean 'filters' - plural?
Does your fuel gauge still work?
Has there been any recent work done on your boat where the floor was removed? Or side pocket on the STB side if enclosed side pockets?

cheers
Brendon

[timddo]

If the breathers are free, then it is a blockage between the pickup and the bulb inlet, not downstream. As a double check for breather blockage, open the filler cap when the bulb has compressed, & if you hear a 'whoosh' it is a blocked breather(s), but as you have two breathers it is unlikely anyway. Out of interest is your boat a Stacer? As others have suggested, first try a new primer bulb. If this doesn't work then some questions..

Not a Stacer- It's a tabs 545.

Is the bulb after the filter or before (re flow direction)?

Arrow is facing to the motor
Has it only happened after the filter change?

Filter is brand new
Did you mean you cleaned the filters, or put clean filters in?
And did you mean 'filters' - plural?
Just one filter, my mistake

Does your fuel gauge still work?

I use a navman fuel flow meter as well.

Has there been any recent work done on your boat where the floor was removed? Or side pocket on the STB side if enclosed side pockets?

Floor was removed, Will check the fuel lines for problems.

cheers
Brendon


Fuel line is enclosed in conduit - so nicks is hard. But will check this afternoon.

tim

[Scott nthQld]

I reckon its a dodgy bulb.

Working back from the motor, disconect the fuel hose and remove or manually open the fuel connector valve (flathead screw driver to push the little bb in works well) and pump the bulb a few times, if the bulb 'sticks' or does not re-inflate after each squeeze, move back to the next break in the fuel line ie the bulb.

Rmove the bulb form the line and using a small bucket of fuel, dip the end in so the direction arrow it point skyward, and the suction end is in the fuel. Give it a squeeze, if fuel comes thourgh and the bulb re-inflates and does not stick, put back into the fuel line and go to the next break, the filter/water separator.

Tedious work, but the best and easiest way to find the problem. Check the seal on the filter, and the coupling, make sure their is no wear or degradation.

[STUIE63]

I have seen a bulb that was assembled backwards (the non return valve was put in the wroing end at manufacture ) once we figured out the problem we put the bulb in back to front and it worked perfectly
You can check by blowing through the bulb
Stuie

[sid_fishes]

tim, mate i have a better idea,,, give gary a call. it can be the best and easiest way to find out whats wrong
cheers champ
sid

[timddo]

tim, mate i have a better idea,,, give gary a call. it can be the best and easiest way to find out whats wrong
cheers champ
sid


That will be last resort. Found the problem anyway, it was a house clamp on the navman fuel flow had perished. Went on my manditory whitting trip today eith the misses. Motor is running smooth.

[Crocodile]

Hello timddo,
Could you provide more detail of the resolution.
You say that the hose clamp had perished, was the clamp some sort of rubber or plastic?
Was the Navman fitting between the tank and the bulb or after the bulb?
Was it somehow squeezing the line?
Thanks

[timddo]

Hello timddo,
Could you provide more detail of the resolution.
You say that the hose clamp had perished, was the clamp some sort of rubber or plastic?
Was the Navman fitting between the tank and the bulb or after the bulb?
Was it somehow squeezing the line?
Thanks

The clamp was between the filter and motor. The clamp was stainless steel too. Apparently it was letting
some air in. Wot was 5200 max. Today it's back to 5500.

The clamp was use to secure the fuel hose.