A couple Mercuiser 3.0 issues, hard to start

jwalz1

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Joined
Aug 6, 2010
Messages
4
Hi folks, I have a 1994 Sea Ray that has been used very little the past few years as it has become difficult to start.

It is the 115 horse version and although it is about 16 years old, has been well cared for and has fairly low hours on it. Once it is running, it restarts just fine and runs well.

Here is the issue, since the boat was new it would always sit at my parents lake place for a week or two between uses and you would pump the throttle three or four times, put the throttle back into the center position and it would fire. Now pumping the throttle does not seem to get any gas to the carb.

I replaced the fuel pump because a new one was cheap, and that did not solve the issue. I took it to a boat mechanic and he said there are about three different spots in the fuel line where there are little filter screens and all were clogged from 15 years of use. He cleaned the fuel filter screens and said it was good to go. I took it to the lake and it worked great. Now it sat for two weeks, took it to the lake and it has the same problem.

Spaying starting fluid into the carb and letting it run off a shot of spray for a few seconds, repeated about 5 or six times will eventually prime it and it will finally keep running. But the fuel pressure seems to be trickling out of the line when it sits for a week and I can not seem to get the pump/fuel system primed without pulling the air cleaner and using starting fluid.

Has anyone had this problem or a suggestion what to look for? I am stumped and don't know why this is happening all of a sudden. Pumping the throttle a million times and running the starter does not seem to do it. It never pulls fuel to the carb where you even get a hint of gasoline smell. Only running the engine of another source (starting fluid) and getting it to run fast will prime it and finally get it going.

Any help appreciated.

Secondly, this is a alpha one sterndrive, and the steering is light as new in one direction but has no power assist in the other. Any hints on what to look at?

Thanks in advance.

John
 

sltintexas

Petty Officer 2nd Class
Joined
May 28, 2010
Messages
109
Re: A couple Mercuiser 3.0 issues, hard to start

I bet that carb needs to torn apart, cleaned, and rebuilt. I did mine on a 3.0 with a mercarb and it was pretty easy.

If you haven't drained that old gas out, I would do that pronto also. Need to get that tank cleaned out.

replace fuel filters as well. If you have junk in your tank you can clog them over and over, even if you just replaced them.
 

jwalz1

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Joined
Aug 6, 2010
Messages
4
Re: A couple Mercuiser 3.0 issues, hard to start

Would rebulding and cleaning the carb have any effect on priming the fuel system?

Its worth a try I suppose but don't really know what the mechanical parts actually prime the fuel pump.
 

sltintexas

Petty Officer 2nd Class
Joined
May 28, 2010
Messages
109
Re: A couple Mercuiser 3.0 issues, hard to start

I am assuming that your system is similar to mine. I don't know that is the case, but I am assuming that. Mine is a 97 and yours is a 94. Mine had a mercarb 2 barrel carb on it.

When the engine is off, and you press down on the throttle to prime the fuel system you should see two steady streams of fuel coming out of the venturi (sp?) inside the carb throat. If you don't, that indicates your first issue. There are lot of valves, jets and passage ways that gas flows internal to your carb. After sitting a while they can get all gummed up. When I bought mine I had to do the same thing as it sat for at least 2 years. On mine though, I did see the 2 streams..but I had a lot of idling, sputtering, and hesitation issues. After rebuilding and adjusting it runs awesome.

I am no expert so hopefully some others will chime in as well.
 

sltintexas

Petty Officer 2nd Class
Joined
May 28, 2010
Messages
109
Re: A couple Mercuiser 3.0 issues, hard to start

also may need to check the fuel pressure at the carb. I know you just changed the fuel pump but should probably verify just in case.
 

Utahboatnut

Senior Chief Petty Officer
Joined
Jan 15, 2009
Messages
785
Re: A couple Mercuiser 3.0 issues, hard to start

Not to sound like a lecture but try and get fixed asap, your engine called and said it really hates the starting fluid its not very good for it.
 

jwalz1

Recruit
Joined
Aug 6, 2010
Messages
4
Re: A couple Mercuiser 3.0 issues, hard to start

I think I found the problem. The check valve coming out of the gas tank seems like it was gummed up and sticking closed. Running the fuel pump off the starting fluid would finally create enough suction to unstick it and then it runs fine until it sits for a week and then the old gas in the tank is gumming it up enough to stick again.

If the theory proved true the carb cleaner on the valve and a few bottles of techron through the gas tank should fix it. Fingers crossed.
 
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