150 Johnson dies from warm start

[Seasport]

Hi all,<br />I have a 2001 Johnson 150. It runs perfectly bar one small problem. If the boat has been running for a while and then I stop for a while (say 10 minutes or more) and restart - the motor starts fine but dies when I try to accelerate. I usually pump up the primer bulb again until it is hard. If I leave it idling when it first starts, it usually stalls. I can get it running fine again if I give the motor a good rev in neutral (which I know is not the best for the motor) and once I am running again all is sweet.<br /><br />It starts from cold just fine. The problem only seems to happen when the motor has previously been run. It needs to sit for a while before the problem appears. Seems to be starving of fuel but I can't figure out why it is happening.<br /><br />Any ideas?<br /><br />Chris

 

[fireman57]

Re: 150 Johnson dies from warm start

Welcome to iboats. Not real familiar with your engine but sounds like crud in the carby's. Buy an OEM manual and some amber and clean/rebuild the carbs one arvo. Then go to the section on link n sync and follow each step.

 

[Seasport]

Re: 150 Johnson dies from warm start

Thanks. Perhaps this is the problem, although wouldn't you expect the motor to run badly all the time if the carbs were gunked up?

 

[angus63]

Re: 150 Johnson dies from warm start

Seasport<br />There are different jets in each carb for idling and high speed. You may not notice high speed performance with restricted low speed jets. A good cleaning and rebuild will never hurt. Also, when you cold start, your motor has a "quick start feature" which advances the timing a few degrees to ease starting and remains on until the motor reaches near operating temp. This effectively raises the idle a few hundred RPM. When you warm start, it only activates for a few seconds.<br />good luck

 

[Seasport]

Re: 150 Johnson dies from warm start

Thanks angus63. A local tech told me that either (i) the carbs have crud/water in them or (ii) the carbs may be running a little lean. He suggested that I richen the mixture a little (1/4 turn at a time) and see if that fixes the problem. I presume you can only adjust the low speed jets on these carbs. Is this difficult to get right on a six cylinder motor? I presume there are six separate jets to adjust.

 

[OBJ]

Re: 150 Johnson dies from warm start

Seasport...check the primer bulb. You might have a bad valve in it letting the fuel partially run back to the tank after stopping.

 

[Seasport]

Re: 150 Johnson dies from warm start

Thanks OBJ. I originally suspected this may be the problem. The primer bulb is mounted so that it sits horizontally on the boat and I'm told this is not ideal for the non-return valve operation. So I give the primer bulb a good squeeze before I start if I've been stopped for more than a few minutes. It usually needs a few pumps to get nice and hard. But wouldn't you expect that doing this would prevent the motor starving of fuel when it first starts? Surely the fuel stays in the carbs?<br /><br />Certainly the motor seems to run fine (including good idling and punch out of the hole) once it's running. The problem only seems to happen when I've stopped for a while and it takes a good rev or two in neutral to get it running smoothly again.<br /><br />Perhaps I should replace the non-return valve anyway.

 

[OBJ]

Re: 150 Johnson dies from warm start

You need to have a good supply of fuel. If the primer leaks back, you won't get that good supply...A good rev may be enough to bring the fuel back up the line and keep the bowls full. Just a suggestion....I might be out in left field.

 

[Rick B]

Re: 150 Johnson dies from warm start

I had the same problem (1996 150 rude) when I switched from champion plug ql82yc to ql87yc. I replaced those plugs because the manual says to for alot of idling. Had same problems as you stated so I went back to the original plugs, no problem since.

 

[Seasport]

Re: 150 Johnson dies from warm start

Thanks for the tip Rick. I'll look at that too. At this stage, I'm inclined to agree with OBJ. The symptoms all point to a starvation of fuel which is just what would happen with a leaky non-return valve in the primer bulb. This may in fact just be because it is mounted horizontally instead of vertically? Do others need to pump up the primer bulb if they have been stopped for half an hour or so? I didn't need to with my last boat.

 

[OBJ]

Re: 150 Johnson dies from warm start

You may also want to look at fuel line conncetions Seasport. Make sure that they are tight at the connection points.

 

[JBL]

Re: 150 Johnson dies from warm start

My friend has the same motor and the same problem. never did find out what it is.

 

[CatTwentyTwo]

Re: 150 Johnson dies from warm start

I have a 94 175 that did the same thing.I talked to an OMC customer service rep at the time and he said I needed to rewet the crankcase by taking it out of gear and advancing the throttle slighty before starting when the engine was warm and had set for awhile. That worked, but the permanent fix was to richen the idle a bit. I did that with the boat in the water, in gear and moving. Have not had that problem since.

 

[Seasport]

Re: 150 Johnson dies from warm start

Ah ha, so I'm not alone. What the OMC rep told you to do is exactly what I found I need to do. Sounds like richening the idle mixture may help. I need to read up on how to adjust the carbs. Is this tricky given that there are six carbs to adjust (I presume)?

 

[CatTwentyTwo]

Re: 150 Johnson dies from warm start

It has been years since I did it. I just followed the procedure in the service manual and I don't remember it as being hard to do.

 

[Seasport]

Re: 150 Johnson dies from warm start

I'll give it a go. Thanks all for your help.

 

[selah]

Re: 150 Johnson dies from warm start

Originally posted by Seasport:<br /> Hi all,<br />I have a 2001 Johnson 150. It runs perfectly bar one small problem. If the boat has been running for a while and then I stop for a while (say 10 minutes or more) and restart - the motor starts fine but dies when I try to accelerate. I usually pump up the primer bulb again until it is hard. If I leave it idling when it first starts, it usually stalls. I can get it running fine again if I give the motor a good rev in neutral (which I know is not the best for the motor) and once I am running again all is sweet.<br /><br />It starts from cold just fine. The problem only seems to happen when the motor has previously been run. It needs to sit for a while before the problem appears. Seems to be starving of fuel but I can't figure out why it is happening.<br /><br />Any ideas?<br /><br />Chris

 

[selah]

Re: 150 Johnson dies from warm start

I HAVE A JOHNSON 150 HP 2000.AND HAD EXACTLY THE SAME PROBLEMS. AFTER MUCH TRIAL AND ERROR I AM TOLD IT IS DUE TO A FAULTY ELECTRONIC PICKUP THAT ADJUSTS THE IDLE FUEL MIXTURE . THE PART COST CANADIAN $73. IF YOU LIKE I CAN FIND OUT THE PRECISE NAME AND PART NUMBER FROM THE MARINA THAT FIXED IT<br />MALCOLM HALES<br />MALCOLM@HALES.ANIKAST.CA<br />CANADA

 

[selah]

Re: 150 Johnson dies from warm start

HAVE A JOHNSON 150 HP 2000.AND HAD EXACTLY THE SAME PROBLEMS. AFTER MUCH TRIAL AND ERROR I AM TOLD IT IS DUE TO A FAULTY ELECTRONIC PICKUP THAT ADJUSTS THE IDLE FUEL MIXTURE . THE PART COST CANADIAN $73. IF YOU LIKE I CAN FIND OUT THE PRECISE NAME AND PART NUMBER FROM THE MARINA THAT FIXED IT<br />MALCOLM HALES<br />MALCOLM@HALES.ANIKAST.CA<br />CANADA

 

[Seasport]

Re: 150 Johnson dies from warm start

Interesting. Yes that would be very helpful - thanks. I haven't had a chance to adjust the idle mixture yet. It's winter here so need a good day for getting out on the water. I also want to check the timing & do a link & sync first. I'm working on an electronic ignition analyser at the moment to help with setting the timing (see my other post).