Johnson 150 2001 fuel feed problems - Help!

[erik_plus8]

Hello!

(I will get the model and serial number soon - it is just after midnight here in Sweden... I think it is a J150PLSIF)

I have a problem: the engine bogs down and hesitates after some running. The time is different depending on which engine revs I'm running. On idle it can run 3-4 min but on 3500rpm it was 41 seconds (I timed it today...).

When the bogging/hesitation occurs I press the bulb 3-4 times, so it gets hard and the engine runs properly again for another 41s...

What I then did:

- I by-passed the filter/water separator connecting the fuel line from the tank to the original BRP fuel hose and bulb that goes into the engine. The engine then ran for 50-60s (at the same engine speed) so the decreased resistance must have helped (I think...)

- I also opened the fuel cap to ensure there was enough ventilation but it didn't seem to have any effect

So guys, please, please help me out with suggestions what the reason for this behaviour can be.

I mean it is a bit strange that the period between bogging was so repeatable - to me it seems like a fixed amount of fuel that is consumed and then the system needs help from the bulb to ensure the fuel feed again.

Also, if it can indicate something: once the bogging started the engine runs properly in between boggning. Like hesitating 5s then running properly a few seconds repeatedly. And like I said - 3,4 squeezes of the bulb and everything is fine again.

Thanks in advance!!!

[RUSTY63]

Welcome to the BBC.

You will need a inline vacuum guage with a clear hose, attach it after the primer bulb, use the guage to check the vacuum from the boats fuel system and the clear hose to look for bubbles, a high vacuum is an indication of a fuel restriction and bubbles are an indication of an air leak.

[erik_plus8]

Thanks RUSTY63,

so rather than perhaps the fuel pump on the engine, you think the problem is somewhere in the boats fuel supply system...?

How much is regarded as "high vacuum"? What can the fuel pump accept?

Thanks.

[RUSTY63]

I don't like to see much more than 1.5 - 2.0 at idle.

[erik_plus8]

Sorry, is that 1.5 - 2.0 <U>psi</U>?

(not used to american units... )

And at some higher speeds like 3500rpm and 5000rpm - what should the pressure be there?

Have now assembled my vacuum meter and some transparent hose and I'm on my way to the boat - back again in a couple of hours!

[erik_plus8]

OK, let's see:

Engine data:

model: J150PLSIF
serial no: G 048/6834

I attached the gauge after the bulb, before the engine:

- At idle there was never an underpressure... It kept the overpressure of 4-6 psi created by the bulb.

- So I then moved the gauge to after the fuel pump, to one of the two main fuel lines feeding the carburators. First I could see a slight overpressure of 2-3 psi (still at idle or just above), but that soon went away and the gauge showed same value as when it wasn't attached (means atmospheric...)

- I then took the boat out to see if higher engine speed could change anything. It didn't... What was very clear to see was that the pressure went up significantly to 4-5 psi when I pressed the bulb when the bogging/hesitation started. So the bulb increases the pressure all the way through the pump out to the carburators.

What this indicates to me is that the fuel pump isn't working, or am I wrong?

With a properly working pump there should be underpressure before the pump and overpressure after the pump, right?

That I didn't see a difference in pressure after the pump at the time when the bogging started (it was already down extremely low, essentially atmospheric) maybe was because the bogging starts only when the carburator bowls are emptied, not before?

I have had all the time since I bought this engine (1.5yrs) problems with warm starts. It was very hard to get it to run properly, and it often died when selecting a gear. Only way around this was to rev it up in neutral, and as soon as the revs are down, select forward and go quite hard on the throttle to get revs up and the boat into plane. Maybe this already indicated that the pump was not working properly???

Thanks in advance for any feedback on these last events!!

PS. Is this the correct part no for the pump: 5004558 if I need to order?

[erik_plus8]

Any ideas of what the fuel pressure should be after the pump (in one of the fuel hoses that feed the carburators?

[erik_plus8]

While waiting for some answers I could add some more information:

My clear fuel line showed that there was never "solid fuel supply" at idle. But since, as I wrote above, I also don't get any pressure out from the pump, maybe a disfunctional pump can cause this behaviour? If the pump doesn't create under pressure from the tank maybe the air never will be vented out?

Another note: The engine has consumed a lot of oil this year - way more than last year...

If anyone can help me in deciding that it is the pump that's causing this it would be extremely helpful since I'm going on a two week trip in a couple of days and I could have the pump ordered and delivered in the mean time while I'm gone.

Any input is greatly appriciated!

Thanks in advance!

[ChampioNman]

Replace the VRO.

[erik_plus8]

Thanks ChampioNman, pump is ordered!

Anything special to think about when pump is installed? Bleeding the oil line must be important, I guess?

Is the mixing rate (fuel/oil) pre-set when pump is manufactured?

Thanks for your support!

/Erik

[lkhartwl]

to be honest Erik there is nothing special to do when you replace the vro. just make sure the hoses are in the right places and just pump up the oil and fuel bulb till hard and start motor back pressure of the bulb on the oil line should hold oil in it till you pump it and not let any air in the line , same with the fuel. the pumping up is just to get oil and fuel into the new vro. I have swapped mine a couple of times checking things and no problems yet ( done under the guidance of ChampionMan) takes about 20 minutes to do the hardest is getting it to line up with the hoses on into the screw holes as the hoses want to go one way and you want it another. Just take your time and it is no problem to do. Good luck, Steve

[Fishaholic]

Pre-Mix the gas in your fuel tank 50:1 with oil, just to be safe. Fill your oil tank and mark the level with a sharpie. Hold the primer bulb vertically when you prime it, to ensure no air is left in the bulb. Once you run it and see the oil level dropping in the oil tank, you can stop adding oil to your fuel tank.
All this info was quoted from SEAHORSE, ChampioNman, Rusty63, and Rudetech1

[erik_plus8]

Thanks a lot guys!

I really appriciate all the advice and tips - great spirit here!!!

/Erik

[SEAHORSE]

You have to do a few tests when installing a new pump. First mix your fuel 50:1 (2%) so the motor will start with mixed gas. Install everything except the oil line. Start the engine and let it run to make sure the NO OIL alarm is functional. It will take several minutes to burn the residual oil in the pump before the alarm sounds. This is assuming that you know the warning horn is working or the SystemCheck lites and warning horn.

After the alarm sounds the NO OIL signal or lite, keep the motor running. Holidng the oil primer ball vertical, squeeze it until a solid flow of oil comes out. Then push the hose on to the nipple on the "VRO" but do not squeeze the bulb any more. Continue running the motor to make sure the oil pump primes itself, by the light turning off or the horn stops beeping.

[erik_plus8]

Pump has arrived. Will pick it up in a few hours. A question came up after reading the answers above:

I have a fixed fuel tank - not so easy to premix fuel in that one. If I run from a jerry-can with premixed fuel I can only do that if I by-pass the water/fuel filter and that is maybe not recommended? On the other hand, what I can understand from SEAHORSE it shouldn't be too long time before it can be decided that the pump pulls oil from the tank, so maybe it's OK...?

Any suggestions or inputs?

[ChampioNman]

Seahorse is correct,you will need an asistant to complete the oil line connection task. What Seahorse means is to mix what existing fuel in the tank with oil to a ratio of 50:1 or 1 pint oil to 6 gallons fuel. no need to add fuel to the tank, just calculate the amount of fuel in the tank and add oil to it. Pull the boat down a bumpy road to mix and then while on the trailer do the connection portion. If at a slip then calculate the fuel in the tank add oil and rock the boat a few times to mix. It won't take long for the alarm to go off.

[erik_plus8]

Pump is installed according to procedures described above - thanks again guys, everything went pretty smooth regarding the pump switch.

However - I discovered a small fuel leak from another fuel hose which had nothing to do with the pump. I had to disassemble the whole bracket where the pump is mounted and discovered a squeezed o-ring. Had no one in spare, but managed to carefully insert the old one properly, will change it later.

To the point - the bracket is mounted with four screws and there are washers underneath them. I dropped one washer when disassembling... I spent an hour just looking for the washer but I just cannot find it.

Can it cause damage when lying there...?

I did a test drive and everything seems OK, there are none of the previous symptoms. The engine is running really well with good throttle response throughout the rev range. I also did a restart at the jetty and also hot starts seem to have improved with the new pump. Remains then the little worry with the washer...

[Bassmeister]

If it really worries you then you can pull the belly pans and get it out ,if it hasn't already fell out.