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Boat Motor advise

2K views 23 replies 9 participants last post by  Sow Trout 
#1 ·
Hello everyone! I am new to this site but have been reading site for awhile now. Very imformative.

I have a 150hp Johnson Ocean Runner. It will not stay started. I have had lower unit serviced, replaced 6 carb bowls,2 carb kits put in, 2 thermostats, water pump kit put in. Anyone know if there are filters I might could check? It fires up, just will not stay started. Any suggestions??
 
#4 ·
Even

if you up the hand throttle? Even if you push the key in to choke when it starts to die?

Pull one of the jet holders out of the bowl and see if there is gas in it once it dies. Might tell you if it's fuel related. Check your hose connections for sucking air and loosing vacum/pull from the tank.

Does it just STOP or does it kind of wind down and stop?

Little more information por favor.

Dale
 
#5 ·
I can up the throttle-still dies.
I will start right up--few seconds later die.
It primes up good and holds good.
I know it is a gasoline issue-just don't know where else to look.

A couple times this weekend if I kept the choke pushed in it would stay started, the second I released it, it died.
 
#6 ·
probably clogged jets. Did you soak the carbs when you put the new kits on them? I've got a few carbs for my honda motorcycle that the jets get clogged. You could try running some injector cleaner through it or soak the carbs and remove the jets. If you are holding prime on the primer bulb it's not a leak letting in air. You could also check and make sure that the tank is not vaccume locked. Remove the gas cap and start the boat...see if it stays running. Possibly some dirt daubbers made a nest in the vent. It happens! I'm pretty sure it's not the fuel pump because you can choke it and it will stay running. I'd say it's probably a fuel filter. Most of the time they bolt onto the engine. Look for a line running from the fuel socket on the outside to the side of the motor.

However if you can choke it to keep it alive you have to have fuel to choke it. I'd say it's the carbs that need a good soaking and have the jets cleaned.
 
#9 ·
Salty,

Again.......make sure you aren't loosing prime somewhere. Sounds like a likely culprit.

When you let it sit to re-start, does the motor have to turn over several times before it fires off? Or does it immediately crank right up?

If the diaphram in the fuel pump is cracked or whatever, that could be loosing prime as well.

Couple of things to consider.

Dale
 
#13 ·
The enrichment circuit is a solenoid that usually takes scavenge fuel and dumps it in the carbs to rapidly fill the bowls up. It is activated when you press the key in then energizing the solenoid.

Does it die while running, idling or both?

I assumed that the carbs had been rebuilt by the posters input.


Dale
 
#15 ·
I feel you just are not getting the fuel to the carb. Choking it cuts the air intake down to match the lesser fuel intake. You have a fuel restriction some where. .....line.....carb jets......????? just got to start eliminating components. Replace the fuel filter........maybe even get a new fuel line/bulb from your tank....or make sure it isn't plugged some how.
You'll find it.....it's just a metter of time !!!
 
#17 ·
In that case, I would take a hard look at the mechanical pump. If one of your friends could get ahold of a Holley blue/regulated fuel pump, I would hook it up and be a quick test to see if that's your problem or not. I have a set-up that hooks on a test tank with leads and it tells you real quick if you have a fuel delivery problem.

Where are you located? I might be able to recommend some folks to take a look at it for you.

Dale
 
#18 ·
SaltyMomma said:
Did That...no Help
So I'd say from the tank to the fuel filter....there isn't a problem. That would have fixed most problems associated from the filter to the tank.. 1/2 way there now. Just go in baby steps ;) Now we need to make sure the filter is letting gas through. Now you have basically individual throttle bodies for each cylinder. We need to determine if ALL carbs are out of fuel or just certain ones. This will eliminate the carbs. Now does it just slowly putter out, or does it sound like 2 or 3 cylinders dieing. I'd let it die. pull the bowls off the carbs and see if there is any fuel in them and how much. If there is no fuel in the carbs....scratch the carbs off the list. It's between the fuel filter and the line going to the carbs. Just keep eliminating elements until you get to the point. If it will continue to run with it choked I'd doubt it's anything in the ignition. If the choke was sticking you'd be too rich and you'd flood out the motor eventually. You're not getting enough gas. Did you say you tried to run it with the gas cap off? What year is this motor. I know some of the newer motors have a fuel restriction horn that goes off.
 
#20 ·
Motors are pretty simple...if you use the divide and concur method of trouble shooting you'll save yourself TONs of time. I work from time to time on the new VW's and with all the electronics, if you don't cut your work in 1/2 by elimination you'll be there weeks.
 
#21 ·
Restricts airflow how? You would have to have a seperate set of butterflys to shut off air into the ventures. Always heard it called an enrichment valve. The valve takes scavenge fuel out of the bowls, dumping it in the idle circuitry on top of the carbs where it finds it's way into the throats of the carbs as raw, un-atomized fuel. This is a mercury design, but I believe it is generic in that sense.

I hope what I am saying is helpful and not argumentitive everyone. I have just been around these dang things for a while. You have got to LOVE fuel injection. LOL


Dale
 
#22 ·
Lazzer I guess it depends on the carbs....on my Honda motorcycle it's got plates that actually come down in the venturi's restricting airflow. The motor is basically an air pump. So as it's sucking, or trying to suck in air, it creates a vaccume. with a greater vaccume inside the carb it's going to pull more fuel. I'm sure different motors have different ways of operating a choke. THe electronic chokes work differently then the manual, vaccume opperated ones. I know on my 35 Evinrude...it's vaccume. I'm trying to find some info on the motor off the net, but can't find much
 
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