50 mercury hp no start

S

steplift20

God
My 1984 50 hp outboard is not starting, she turns over and pops sometimes but does not start. She started last month. What to check? Spark yes,got it. Battery charged to full. Must be something going on with the gas any suggestions ?
 
you seem to have narrowed it to fuel, unless it suddenly lost compression, so any filters to check. ball pumping up and getting hard. no fuel leaking from carbs?

choke working?

pull plugs out, squirt some premix gas in, see if she pops off
 
Ok I will do that. I got her started after I took off the fuel filter and filled it up. It’s the little plastic cap with 5he screen inside. She started up ran for a short time than stalled.
The screen filter looked good but what I’m go8ng to do next is try to run her without a filter than if she starts. That’s the issue if not. Do what you said. It’s a great engine but l8ke all engines ,when they don’t run,,,,,they suck.
 
Ok this is where I’m at, put some gas in the spark plug hole and she started right up then shut off. So I’m confident that she is not getting gas. I took the gas line off at the fuel filter going to the cards and it was under pressure , gas is flowing to the filter but I’m thinking ,should it be pressurized. Going to the carbs? I had the carbs rebuilt last year what should be my next move? Thanks for any feed back
 
6 gallon tank or built in tank?

Quick disconnects on fuel line?

Go buy a qt of Trufuel 50:1 E free fuel.
Disconnect fuel hose from tank.
Stick it in the Trufuel can
Pump ball till firm
Start motor

If it doesn t start, problem is upstream. . . Fuel pump then carbs
If it does start, problem is downstream. . . Filter,tank pick up,connection.

Also, i know u run ethanol, so could be collapsed lining in fuel line

If it does start on the Trufuel then dies, try holding the can higher than the engine. This will give u a flooded suction to the fuel pump and make it easier for a weak pump to pump fuel. I used to be able to tell when my fuel pump was getting weak on my old Merc because after trolling about 15 minutes, it would get slower and slower. Would have to go back and pump ball.
 
Tried two differant tanks. If I put gas straight into the carbs she starts up. I feel it’s a carb issue. I had them rebuilt last year but honestly where I liv3 the mechanics are not the best if you can find on3 who works on an old engine. I mean. A carb is a carb.
 
Carbs cant carb if fuel is not getting to them.

Pump ball hard and open bowl drains on carbs, see if gas is getting to them.
 
No gas to bowl. You know what really sucks,I had them rebuilt last year , I went back to him and he said it’s probably the needle. Ok than he says it will cost about $500.00 to rebuilt the two carbs. He did it a year ago. I liv3 by lake hopatcong and the so called mechanics here are not good like down the shore. I think im going to wait till next year. The people up here are nice the the mechanics suck
 
Phatdaddy ,youknowi didn’t check that.im going to disconnect the fuel line going to the carb and see if it’s clear. That’s a very good point, start with the simple and work your way up. I’m going to look at that tomorrow
I will post here with the results. I hope the fuel line is bad,that would br great.
 
Hey Step - I’m not an outboard guy, but I do have a lot of stuff with carburetors. To check if that guy’s needle comment MIGHT be correct (could also be a plugged passage or jet in the carb), and you can drop the float bowl, if there’s gas in the bowl, you’re probably getting gas to the carb(s).

That would be after checking the fuel line like Phat said and being sure you’re getting good fuel flow past the filter. For that, I’d test it by pulling the fuel line off the gas tank and motor and putting some air pressure in the tank end to see if the flow is good. Pretty gentle pressure should send a good flow.

My $.02 worth.
 
The problem with removing the bowl is if I do than to reseat it with the gasket is very hard u less you remove the carbs,and I don’t want to do that. Only last resort. But if I hold 5he bowl in place and back off the screw holding it ,gas should leak out through the screw hole. Right?
 
I disconnected the fuel line going to the carbs,I blew air through it and the bottom carb blew gas out of it but not the top carb. I did get it started and seems good. I shot carb cleaner through the carbs while running. And she ran for a l9ng time till I shut it. Now ,will she start tomorrow? I will let you know. If she starts then I think she is good. I***8217;m hoping it will be good
Scook I did what you said with the air. So far so good.***55357;***56842;
 
No good. It started on the first try Great, then it stalled out and didn’t start again. But I noticed that the primer bulb is rock hard ,so there is no gas flowing to the carbs, is 5here @nything that I can do without removing the carbs? What to look for.
 
I m confused. U disconnected fuel line at carbs and blew air toward tank. When u did this fuel came out of bottom carb. How did the air get to carbs if u disconnected the fuel lines to them?
 
No ,I disconnected the fuel line from the inline filter and blew air in the line going to the carbs, the bottom carb blew air and gas out the top carb did not. But yesterday it ran great so today I started it and she started on 5he first try,then stalled out and could not restart it unless I put carb cleaner into the top carb,than it started but stalled so I think the problem is with fuel getting to the carbs. I think what I’m go8ng to do next is remove the fuel lines (. It may) and replace it with new fuel lines. I don’t know much about carbs so I will leave them alone but check the lines. What do you think?
 
Again, not an outboard guy, but I would unhook the fuel line at the tank and at the carbs and blow air from the tank end through the whole fuel line/filter system. That way you know that fuel is getting there. Not blowing very hard, so you get as close to an actual conditions test as you can. If the fuel line(s) look crumbly or swollen on the inside, definitely replace all of them. If they’re at all crumbly, a chunk of the line could be in the carb(s) intermittently blocking flow.

With the fuel lines off the carbs, can you squirt some carb cleaner pretty hard in the fuel inlet on each carb? That should have some chance of freeing up a stick float needle and possibly clearing other passages.

If that fails maybe check to see if SpareParts would be willing to rebuild the carbs if you sent them to him?

That’s my best shot at it. There may be some diagnostic YouTube videos that could help, but it really does sound like something in the carburation is plugging up.
 
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