New primer aswell? Mine is cracked, which reminds me I gota replace it before it splits and sucks air

Fuel screen filter housing?
Thu, 2012-03-15 20:41
I had an older model 2 stroke Johnson years ago.

I found that they seem to have a fairly easy to fix problem where the fuel supply line joins onto the motor.

If you pump the hand priming bulb on the fuel line then have a look at the black plastic housing where the fuel supply line goes onto the engine. Often they get a very small hairline crack and it will cause the carburetor to suck air along with the fuel. The housing normally has a small bolt on the centre with a flat blade screwdriver head fitting. Undo the bolt an you will remove the housing and a small screen filter.

They are fairly cheap to replace $10 or so.make sure you get a good seal but don't over tighten the new fitting.

I suggest giving this a go first of all. If u are in the metro and you get stuck then let me know and if u are not miles away I could possibly take a a look.

How do you know its a fuel (pressure) problem?

you say the motor suddenly cut out.

If it was fuel, i would think the motor would play up a bit first before stopping.

Suddenly cutting out would more likely be ignition.

Thats my opinion anyway.

Iana, loss of fuel pressure can cause your motor to cut out suddenly if it is a large enough leak & it occurs suddenly. Scano could be onto something with the fuel filter housing, I replaced that exact part on mine because it developed a crack that was causing it to lose pressure & cut out sometimes. The other thing to check is the fuel lines under the cowling, I've had one fail on me suddenly causing the motor to die. Hook the fuel tank up with the engine cowling removed & squeeze the bulb until the pressure builds up, then squeeze it a few more times & see if you can see any fuel coming from anywhere or if wet spots start appearing. If you can't see any of that grab a straw & have a sniff around the fuel system, without actually sucking up anything except vapours of course. When you find where the fuel smell is strongest yo should be in the general area of the fuel leak. 

Got the day off work so I'm gonna have a good look at it today. The motor did cut out but managed to get it going and get back to the ramp by squeezing the primer as it ran!

Sounds like a blocked filter or a dodgey fuel pick up pump!

When you find the problem make sure you let us know!

I'm stumped! Can't figure it out!

Iv got no real outboard exp, but it prob a carb engine, pull the bowl off, if its dry, there maybe an issue with needle and seat/ float. If its full of fuel and theres shit in the bowl, that couldav gone through blockin a jet or something. There must be a fuel pump before the carb tho, may be faulty.....fuggen toow strokes

Have you tried running it with the choke on? If so did it run ok with the choke on??

Try (CSR / Clean-R-Carb )you can get it from Auto One in a spray can.Spray some of that through the motor when it is running (in the fuel hose )i use it to clean the crap out of the carby.You can also do a reverse gas line check,put the soapy water on the inside of the hose (disconnected from the motor that is )and put small amount of pressure in the line to see if it leaks.

So the tank is fine, breather all good, fresh fuel etc?

Fuel line is on the right way - no holes or leaks?

Then it comes back to engine if not those two and would start getting into mechanic range if you really want to get your confidence and piece of mind back in the old girl imo.

Hey Mate,

Im pretty sure your problem with you engine is the diaphram pump.. It is a little pump that bolts on the side of the engine with 2 screws. It works on a vacuum system.... One way to make sure it is 100% that pump is to start it with the choke on and see if it runs. If it runs and when you take the choke off it dies, it will almost 100% be that pump. All it takes is a little pin hole in the diaphram and you wont have fuel pressure. The pumps are not that expensive to replace, and from experience it is better to replace the pump instead of trying to rebuild it.

Let us know how you go

Yep, fuel pump works on crankcase pulses on a diaphram, if you pull the hose off that is between the pump and the carb and pump the primer, fuel should come out, then turn the motor over, if no fuel pumps out then there is an issue with the pump likely to be the diaphram, heres a pic of what the pump should look like, may be bolted to the engine

Obviously if you can keep the motor running by pumping the primer, you are acting as the fuel pump and there is no blockages but there is a screen inside the black cover which is the intake and you may also have an inline fuel filter that would be worth checking

Heres where it is on the engine...

Tim - O

Your spot on there buddy!!

If you use the choke it draws more fuel and air thus creating more of a vacuum inside that pump.... It is just an easier way to check it rather than taking those fuel lines off..

Be interesting to see if we are right!! haha

The inlet should be the large hose with cable tie, the pulse hose is the one seen right of that and the outlet to the carb/s is behind the inlet hose next to the pulse one..... 

This may help too, may need to select the specific model if there are differences, some pumps dont have the pulse hose if iis bolted to the crankcase

http://www.boats.net/parts/search/BRP/JOHNSON/2005/J55MLSOR/FUEL%20PUMP,%20%20FILTER,%20%20BLADDER/parts.html

Took me 5 min on google for all this, its all there on the internet.....Iv downloaded a full workshop manual for my honda 50 for nothin online

Check the o ring where the fuel line plugs into engine.  A small crack in that o ring will suck air and may be your problem.  I had a bitch of an old motor which was never running right, until I got a free o ring from work and it was now fixed

Thanks tim-o pretty sure the diaphram pump is the issue... big thanks to fisherking for having a look at it when he picked up his strecther