Carburator Problem??

[steveas0321]

The reason I say that with a question mark is because I'm not really sure that's the problem, but likely it is. I'm a fare mechanic but only been tinkering with friends boat (atomic 4) for a while. I'm sure I could take the carb apart and spend endless house rebuilding it. Not really into it. I was thinking of just buying a new one and being done with it. If that's a good idea? Boat is about mid 1970's 32' Islander

Engine has always ran well. Some choke problems, idle problems, but all in all not bad to live with. Well, the other day she just decided to give us fits on a short little sunset sail. Going out of the harbor died several times.... restart.... struggle.... jetty.... Made it out. Coming back in died after a couple minutes.... restart.... struggle.... jetty.... Made it to the slip. I not good with stressing about running aground.

Fresh gas, getting fuel, electronics OK. Question is to rebuild or not to rebuild? The carburetor looks simple enough but just haven't gotten into it yet. Is it worth it?

HELP!!!

[JOHN COOKSON]

Yes it's worth a rebuild if the carb is the problem.
Mechanical or electric fuel pump? If electric try bypassing or shorting across the OPSS (oil pressure safety switch). Sounds to me like you are running on one carb bowl full of fuel then the enging dies.

TRUE GRIT

[Loki9]

The carb is simple to rebuild. In many cases, you can just open it up and clean it, without replacing anything. If dirt in the carb is the problem, it may return quickly if you don't find the source of the dirt.

[hanleyclifford]

You didn't mention filters. These days it is necessary to have a filter/separator right at the fuel tank and a secondary "polishing" filter just before the carb. Courtesy of ethanol and your intelligent government.

[steveas0321]

The carb is simple to rebuild. In many cases, you can just open it up and clean it, without replacing anything. If dirt in the carb is the problem, it may return quickly if you don't find the source of the dirt.

Is there a rebuild kit? i.e. gaskets, springs screws etc? Or just go for a good cleaning and hope you don't tear anything?

Adjustments?

[steveas0321]

Pretty sure filter and pump are good to go.

[Loki9]

There are rebuild kits available from www.moyermarine.com like this one.

You'll need to determine if you have an early or late model carb to choose the right kit.

There are no adjustments inside the carb, just the idle mixture screw on the outside. Some early models also have a main mixture control (external screw) but the late models are fixed.

You may not need any parts, or maybe just a gasket that can be ordered separately.

[hanleyclifford]

Perhaps if you drain the bowl (plug at bottom of bowl) into a clear glass container you might see some contaminants.

[yeahjohn]

You can break down the carb in 30min. Just pull it apart and have a look. Read up on cleaning tips etc. Like use a piece of wire to clean ports and jets and all of the other things to inspect. I have never used a rebuild kit. I have one but a basic cleaning always does the trick. It sounds more like a fuel pump issue. Carb will normally refuse to run, not run, need choke, not restart immediately. Check your filters and fuel lines too.

[prstack7]

Easy

When I first had problems a few years ago, I thought cleaning the carb would be difficult. I was so wrong. 2 bolts to remove, 4 screws to disassemble, a new gasket (the carb had never been removed in 33 years), soaking in carb cleaner, wire in orifices, done. I experienced starting then stalling before I cleaned the carb. I'm guessing some gas got through, but then not enough. I thought the problem was the pump (a good reason to have a fuel pressure gauge), so I replaced that and things worked for a short while (probably just because it increased the pressure slightly). But then stalling returned. After I cleaned the carb, engine roared to life and has run great since.

[steveas0321]

When I first had problems a few years ago, I thought cleaning the carb would be difficult. I was so wrong. 2 bolts to remove, 4 screws to disassemble, a new gasket (the carb had never been removed in 33 years), soaking in carb cleaner, wire in orifices, done. I experienced starting then stalling before I cleaned the carb. I'm guessing some gas got through, but then not enough. I thought the problem was the pump (a good reason to have a fuel pressure gauge), so I replaced that and things worked for a short while (probably just because it increased the pressure slightly). But then stalling returned. After I cleaned the carb, engine roared to life and has run great since.

Sounds like a good cleaning is what it needs to me as I checked everything else and all seems good with fuel system...... Likely get into it next weekend.

Thanks to everyone for comments and support. I'll post my results.

[steveas0321]

Cleaned the carb!!!!!

Everything taken off and cleaned. Pretty simple job.

One question. What is the setting for the needle valve?

When I took it out.... it was 4 to 5 full turns in clockwise..... nearly bottomed out.

Is that right? Only 1/4 to 1/2 turn is all that's left to complete bottom???

HELP???

[Dave Neptune]

Idle mix

Set the idle screw at 1 1/2 turns open~IE screw it all the way in to the seat GENTLY then back it out 1 1/2 turns. That is about where most idle, you will need to adjust a bit from there once running.

Dave Neptune

[steveas0321]

Carb adjustments

Can anyone help me with the proper adjustments (initial settings) on the carb? FYI - this is an older one.

1.) The fuel mix valve at the bottle of the carb...... Is there a certain setting to start with? I had it all the way in (no start). Backed it out about four full turns and engine started.
2.) There is a needle valve on the top (side) of the throat. I am assuming that's the idle screw and will set it according to last post.......
3.) I've played around with the idle screw on the throttle arm. There's no mysteries there.
4.) Engine starts with choke all the way out. Push it in about 1/4" to 1/2" in once it starts. Even after the engine is warmed up you can not push the choke all the way in or it will die..... Is that normal?

THANKS

[Dave Neptune]

Also

Aha, didn't catch that is was an old style carb with the adj main jet. If I recall properly the main jet sets between 1 1/2 ~ 2 turns off of the seat. You will need to be running hard against the dock lines to adjust the main and then do a better results type adjustment when out and at hi cruising speed. You should be able to get a decent idle adjusting in the slip.

If you still have problems running without the choke check the gaskets for integrity, you may just have a vac leak.

Dave Neptune