1996 Merc. 3.0LX cranking issues

[Schmoe]

LONG time reader here, not a lot of posting. However, I need some advice. Couldn't get the boat to crank up this weekend. First time in 20 years I've ever had one single problem with the boat, so I can't be too unhappy, but she needs to be fixed. Back into water, outdrive down, crank. Kill switch is on RUN position, turns over just like she always does. Half tank of non-ethanol fuel in the tank. Will not even hit or sputter. Took breather cover off, not fuel smell coming out of it. This is the Mercarb. Boat always stored covered and inside a closed garage. Took off the output side of the pipe from the fuel pump to carb, and no residual fuel coming out of it. I poured some fuel into the carb, and it did crank for about 5-6 seconds. It was mid day and didn't have the time to check the fuel pump. It is a mechanical pump. It is still factory, as with the carb, has never been touched since birth in 1996. Low hours. Been an absolute joy to own. Can turn a wrench, but messing around with the fuel systems makes me nervous and need some more information before I try and tackle this. My spidey-sense tells me it's the fuel pump or something within that area. I couldn't get to the glass bowl to see if fuel or water or if anything was in there, would have to do that blindly and not sure what would happen to the fuel coming out of the fuel tank. I mean, if I could loosen the glass bowl, would all that fuel stored in the tank come rushing out? There is no shut off valve between the fuel pump and fuel line. Appreciate any comments. My merc mechanic I use sometimes for impellor replacements, is talking new fuel pump, total carb rebuild and then dialing it all in for around 600 to 700 bucks....ye-ouch. Wondering should I take the plunge and get a rebuild Rochester for about 300 ish and new fuel pump, 100-ish and just put all new stuff on it? I have a feeling the carb is fine, but with the age of it....things are bound to go bad eventually.

 

[CV16]

Have you changed the fuel filter? Might be one in the line right at the carb and then the water separator.

 

[KJM]

Sounds like your mechanic has dollar signs in his eyes. I would not jump to those expensive solutions without at least a little detective work on my own. Like CV said, water separator and fuel filter needs to be checked first. Then check for fuel flow where gas line enters the carb. Then blow back to the tank from the rubber line that enters the water separator or where it enters the fuel filter, to check for obstructions. There's an antisiphon valve on the tank end that can malfunction. Maybe there is dirt in the tank and the fuel pickup in the tank is clogged. Your mechanic could be right but why jump to the most expensive options before you even know the problem. Even if the fuel pump is gone, why rebuild the carb too if everything was working fine before or if the carb is the problem why replace the fuel pump? they are likely not both gone.

 

[Schmoe]

Appreciate that. Honestly, I didn't even know there was a fuel filter on it. It's inside the fuel pump itself, one reason I couldn't find it searching around the engine bay. Was assuming it would have been some sort of an inline type filter, not inside the fuel pump. Yes, I will definitely check that first, just a PITA getting to it....but....I'd rather do it than having to pay someone for that extra labor. Will have to remove a side panel, but I've done it before when I replaced the starter. I have a feeling that may be the problem. Appreciate the help my friends.

 

[KJM]

Be careful when taking off the housing with the filter in it. there may be a spring in there, its gone on mine but I think there may have been one there at some point. anyway if there is it will be a bigger PITA fishing around under the engine looking for it. Also there is usually another small filter or mesh screen where the steel gas line enters the carb, or at least there is on my older engine.....

 

[Schmoe]

You think it would be easier to just take the whole pump out? Once the fuel lines are removed, only two bolts hold the pump on to the block.

 

[Bondo]

I couldn't get to the glass bowl to see if fuel or water or if anything was in there, would have to do that blindly and not sure what would happen to the fuel coming out of the fuel tank. I mean, if I could loosen the glass bowl, would all that fuel stored in the tank come rushing out?

Ayuh,.... What's this Glass Bowl thingy yer talkin' 'bout,..??

There shouldn't be any Glass anything in yer fuel system,.....

Post a picture,...

 

[Schmoe]

My mistake, I assumed it was glass, but couldn't see it, it's metal, just like all the others.

 

[Schmoe]

Finally going to get some time to get back to the boat for a couple of hours tomorrow and start looking for the problem. I plan to start with the fuel pump filter. What would be some of the tell-tale signs that that would be the culprit? Obviously clogged filter, broken gaskets?? If that looks good, then planning on taking of the fuel pipe from pump to carb and looking at the carb filter screen and checking the pipe itself to make sure it's not obstructed. If that all checks out, then probably take out the gas feed line to the fuel pump and see if there is fuel coming from the tank. If that checks out, just remove the fuel pump and either rebuild it or get another one.

 

[Schmoe]

Took fuel line off the fuel pump inlet, fuel flowing fine from tank, but noticed the fuel pump itself was actually barely hanging on. Took off fuel line from pump to carburetor, then tightened down the fuel pump and it was really loose. I'm assuming that it's a dry hole that the fuel pump lever goes in because there is just no way oil would have stayed in the engine and all over my bilge. As I was tightening the fuel pump, noticed fuel coming out of the out line on the pump, so told me that fuel pump is probably OK. Went ahead and took carb off and rebuilt it. It was pretty gummed up so it needed rebuilding, also, this is the Mercarb, which has had some problems. Boat sprang to life. Once getting it dialed in, no more bogging from a dead stop. Nice. Working great now.

 

[harleyman1975]

Great to hear! thanks for sharing the "fix" !