Outboard Preformance Issues

[zippy83]

Hello All,

Just had some time to get out and try the boat out. Everything seems fine until the afternoon. On my way back when I fired up the outboard and wanted to accelorate the outboard would turn off. When it turned off I heard some noise come from it almost like there were some lose bolts and nuts in there. After I fired it up again it would go about 3-5 mp/h without any issues but when I wanted to accalorate it would staert to shut off. After I played with it a litle by trying to accalorate and when I noticed it would die I would pull up the thottle towards neutral to keep it running. After a couple of times by douing that it would finally accalorate to 30.00 mp/h. then I would stop and put it back in neutral and then in forward again and it would go without shutting down.

After I got back to the ramp I would turn it off and turn it back on try to fo forward and it would shut off again if I wanted to go over 5 mp/h. My machanic is busy for the next 4 weeks so he cant look at it untill May. I was wondering what could be causing this issue? when it runns it runns great!!

Motor is a 1974 50HP Mercury 2 stroke. I did the regular maintenence (lower unit oil, spark plugs, etc)

any thoughts?

Thank you

 

[JimS123]

Re: Outboard Preformance Issues

Sounds like a carb issue. Don't run it like that until you have it checked out. That vintage Mercs were noted for carb problems, which resulted in throwing a rod because of running a lean cylinder.

 

[zippy83]

Re: Outboard Preformance Issues

ooooo what a shocker... maybe this is a sign to start thinking about a newer outboard. I dont know if a repair is worth it this time. if you think about it no one makes new parts for these older engines, so whatever gets replaced/repaird might even come off an older outboard.

 

[saumon]

Re: Outboard Preformance Issues

Parts are still available, and a carbs overhaul (not only cleaning) and fuel pump diaphragm replacement shouldn't cost more than $30 in parts so it's worth trying it.

I agree with JimS123, it looks like a fuel starvation problem. Could be a plugged jet orifice, or a punctured fuel pump diaphragm...BTW, if you've never done it, it is also part of a regular maintenance, and easy to do.

 

[zippy83]

Re: Outboard Preformance Issues

Parts are still available, and a carbs overhaul (not only cleaning) and fuel pump diaphragm replacement shouldn't cost more than $30 in parts so it's worth trying it.

I agree with JimS123, it looks like a fuel starvation problem. Could be a plugged jet orifice, or a punctured fuel pump diaphragm...BTW, if you've never done it, it is also part of a regular maintenance, and easy to do.

The problem is that I have never worked on an outboard before so I wouldnt be able to replace the card or the fuel pump myself. I can be sure that the mechanic will charge me $400+ to do that. When I got my water pump changed by him I had to pay 279.00 for that only.

When I got this boat the guy I purchased it from texed me a few weeks later saying that he found out that the fuel hose from the tank to the outboard was recalled. I dont know if that has anything to do with the problem I am experiancing.

 

[saumon]

Re: Outboard Preformance Issues

Maybe; carbs sometime get plugged with debris from the inside of old hoses that deteriorate.

Because it run, even at 5mph, mean you have compression and spark so the problem is definately related to the fuel supply. In this case, the first thing to do is to connect the engine to a portable tank with another hose/primer bulb assembly, to rule out this part (bad gas, junk in tank, deteriorating hose, bad primer bulb) as a possible cause. If it still act out, then proceed to the carbs and fuel pump.

Carb cleaning is, really, one of the easiest thing to do. Loosen everything (remember what goes where), spray with carb cleaner, blow with compressed air and reassemble. You'll need a service manual (OEM preferably or, in this case, a generic like Seloc could be ok) for the float height, mixture setting and link&sync procedure (as a rough setting, you set the float parallel to the base of the bowl and the mixture screw 1 1/4 turn out).

Like I said, it is part of regular maintenance and, according to the symptoms you describe, you could probably fix it for not much by yourself. Go get a Seloc manual and learn how to do it, you don't have anything to lose...

 

[zippy83]

Re: Outboard Preformance Issues

Maybe; carbs sometime get plugged with debris from the inside of old hoses that deteriorate.

Carb cleaning is, really, one of the easiest thing to do. Loosen everything (remember what goes where), spray with carb cleaner, blow with compressed air and reassemble. You'll need a service manual (OEM preferably or, in this case, a generic like Seloc could be ok) for the float height, mixture setting and link&sync procedure (as a rough setting, you set the float parallel to the base of the bowl and the mixture screw 1 1/2 turn out).

Like I said, it is part of regular maintenance and, according to the symptoms you describe, you could probably fix it for not much by yourself. Go get a Seloc manual and learn how to do it, you don't have anything to lose...

I guess I can try cleaning the carbs. I have some manual that i was given a link on another thread. I will also replace the fuel hose while I'm at it

 

[saumon]

Re: Outboard Preformance Issues

Ok, here's the manual:

Small Engine Repair Reference Center Home: MERCURY - MERCURY FOUR-CYLINDER MODELS (1969-1989).

Here's the carbs kit (I don't check if yours is a 2 or 4 carbs):

Mercury Carburetor Kits - iboats

And do the same for the fuel pump (I don't know your serial #):

Mercury Fuel Pump Kits - iboats

I hate to see a good engine being put to junk when a simple fix can get it running...

 

[zippy83]

Re: Outboard Preformance Issues

Thanks Saumon... I will give it a shot this weekend if I get some time. I will post back with the resoults soon.

 

[Bob_VT]

Re: Outboard Preformance Issues

Moved to Mercury forum

 

[CharlieB]

Re: Outboard Preformance Issues

Zippy, I'm out in Wrigiht City, send me a PM and we can talk about you dragging the boat out here and I can teach you how to take care of it.

Charlie B

 

[zippy83]

Re: Outboard Preformance Issues

pm sent

 

[zippy83]

Re: Outboard Preformance Issues

Took the flywheel, starter and a few other things off to get to the two carbs. The fuel lines were leaking fuel, I was able to get those replaced and change the fuel filter. Also cleaned out the carbs and replaced some stuff that i was able to. Although I don't know what all those things are called but seemed like some sort of seals. Put everything back together and tested today. Works good all though It was just a test run, the weekend will provide more info it that was it. If not CharlieB will be getting a boat in to check out

 

[saumon]

Re: Outboard Preformance Issues

If fuel lines were leaking fuel, chances are they're also sucking air while running and simply replacing them could have solved your problem. Let us know what's the result of the test run...

 

[zippy83]

Re: Outboard Preformance Issues

Took it out to the water and ran into a small problem at first. When I turned the engine on it wouldnt stay on in idle, it would not die right away but you can hear it was running crappy. When I replaced all the fuel hoses, fuel pump, filter and put in new re-built carburators I fired it up in front of the house and it was running in idle for 15 min or so. Now on the water it was dying.. The only diffrance I did in between the runs is I have oppend the fuel tank up and replaces the gasket where the fuel line pluggs into the fuel tank. I had to take out the whole thing (the tube and measuring cork) and I wonder if Maybe air went into the system or something.

When I ran the motor I had 0 issues. I actually got 2 extra mp/h out of it topping at 31.9 mp\h. After running for a while I had it in idle and it didint shut off. I may be hearing that the motor is running a bit diffrently from the sound of it but I cant say for sure, maybe its just me. I had it runn in idle for 15 min and shut it off, turn back on and let it run in idle and it was fine. So maybe it was litle air I dont know.

I will get a new bigger tank (9Gallon) now that the outboard is running fine 6 galons is not a lot of fuel for a long drive.

 

[oldman570]

Re: Outboard Preformance Issues

You might be better off tyeing two 6 gal. tanks together and carrying a spare 2 1/2 gas and extra oil so you can mix more fuel when the 12 gal. is dry . That way you could get to some where to buy more fuel. JMO
Oldman570

 

[zippy83]

Re: Outboard Preformance Issues

You might be better off tyeing two 6 gal. tanks together and carrying a spare 2 1/2 gas and extra oil so you can mix more fuel when the 12 gal. is dry . That way you could get to some where to buy more fuel. JMO
Oldman570

12 GAL wont fit under my deck in the back. The biggest one I can put in that storage is 9 gallon.

 

[zippy83]

Re: Outboard Preformance Issues

I think I found out what the problem with the IDLE might be. I may need to adjudt the idle speed a litle