Ok, Now I'm Frustrated!

CoralReefer

New Member
Mar 26, 2008
685
Nashville, TN
Boat Info
1987 250 Sundancer
Engines
260 Mercruiser w/Alpha I
Ok, now I'm frustrated. My mechanic came out and put a new carb on and it ran great and idled fine. Today I went to start it up and run and darn if those idle gremlins are back.

The only thing different about today is that the flame arrestor was bolted on. I cleaned the flame arrestor today with carb and choke cleaner too.

Could the arrestor that's on it somehow be choking the motor? I'll try tomorrow to run without it to see if that's it. Has anyone had any experience with this stuff?
 
The person I bought the boat from said that it's had some performance motifications and I believe a slightly bigger cam. Thanks for any suggestions.
 
Highly unlikely the that the flame arrestor is choking the engine, especially if you cleaned it. Besides, if the motor can start with it on it should be able to idle with it on. To start with I would look at the following:

Do you have a filter/water separator on the fuel line? If not, possibly bad fuel or contaminated.

Is the choke electric?
 
No choke at all. The boat has about 1/8 to 1/4 tank in it and I haven't been able to put any fresh fuel in it. Should I get about 5 gallons and put in to see if I can dilute the trash? I want to fill it up but I won't dare to get it out of the slip until these bugs are worked out.
 
I just saw your other posts in another thread where you were describing the "new" carb that you bought off Ebay, so let us back up a moment.

Firstly, is the carb a new marine carb... as in new in the box, rebuilt or used?

Secondly, are you able to determine if there is a fuel filter/water separator in the fuel line as I asked earlier? If not, then you will need to disconnect the fuel line and draw a sample of fuel and check for water and/or dirt/rust.

Do not put any more fuel in the tank until you check this first!

Let me stress a couple of things:

1. The only good carb is a brand new one or one professionally rebuilt.
2. An old boat lacking the aforementioned fuel filter/water separator will be towed back to the dock (sooner or later) even with a brand new carb.

I'm sure you are anxious to get out on the water with your new boat but you need to be patient and get this sorted out first. Trust me, you'll be glad you did!

Jack
 
The carb I purchased was professionally rebuilt by "I-Five" Components and it is a marine carb ("J" tube and slotted throttle plates)

It does have a fuel/water separator and and we put new filter and plugs in first thinking that was the problem.

I suspect it's a dirty or broken down fuel issue. I don't suspect a fuel pickup problem since it runs under throttle.

Hopefully my mechanic that came down to put on the carb will make a return visit w/out charging me another fee but I won't hold my breath on that. Thanks for the help and let me know if anything else comes to mind.
 
Your post said... "no choke"? Do you mean the choke is off or actually not there? How old is the fuel? Have you checked for vacume leaks around the base gasket, check tighten the bolts etc..... lots of variables to consider
 
I'm not a mechanic but I'll try to describe it the best I can. There is a choke on the carb but not able to work. There's a bolt broken off on the intake manifold (something to do with the coil that pulls the choke off when heated). The old carb on the boat just had a zip tie holding the choke open.

The boat runs under throttle but as soon as I start easing back to idle it just dies. Again, when we put the new carb on yesterday it ran and idled fine which still remains a mystery to me.

My best guess now is a fuel quality issue since the 1/4 tank in it is about 8 months old. I know that the owner put treatment in it when stored. I've been researching on the internet all day and the fuel quality issue sounds like my gremlin. I just hate that I put a new carb on the boat thinking that was the problem and now I'm back to square one.

It hasn't been such a pleasant "first boat" experience so far but I'm going to be patient and work the problem through.:smt021
 
Today when you started it up, did it warm up before bringing the throttle back? With no choke it is not going to idle until warmed up a bit. When it quits, does it just kinda slowly go away or just go dead? Assuming it was warmed up and will still not idle..... is there sooty smoke from the exhaust? {overfuel from a stuck float}
 
I maybe let run for about two minutes. I don't think I'm running a thermostat and I didn't pay attention to the temp guage so maybe I'll try running it longer tomorrow. The only reason I didn't run longer was that when we put the carb on yesterday we didn't have to run it but a minute and it idled fine.

It slowly went dead and no sooty smoke.
 
I'm about 75% convinced that it's bad fuel. Does anyone know easy it is to get the fuel tank out of this boat? Any experience correcting this problem in your boat without pulling the tank?
 
Are you running this in the water or on the trailer? One thing to keep in mind is that the floats on this carb need to be set with the boat in the same plane as it would be in the water. IN other words if your running it on the trailer and the bow is up in the air it is going to have an effect on the float settings. Lasthing I did when I rebuilt my carb on my old cruiser was to launch it and set the floats. Ran like a top. Hope this helps. MikeR.
 
It's in the water in the same spot as the day we put the carb on and it ran fine. :huh:
 
My bet is that not having a choke, and a t-stat is causing your problems. You can get an electric choke to put on that carb.

I would run at fast idle, about 2000rpm for a good 2 or 3 minutes. If it still dies out after that, you have a problem elsewhere.

First, get a choke, and a t-stat.
 
I did just that today. Patiently started and let fast idle for about 3 minutes...ripped the throttle a couple of times....pulled back and what do you know. Maybe I should be more patient and make sure it's warm. I know that some boats don't have thermostats. My temp guage either doesn't work or it runs real cold. Hopefully problem solved. Thanks.
 
You SHOULD run with a t-stat. You will do internal damage if not running at the correct operating temp. You should have a 140* stat in that motor.

My 8hp 2 stroke outboard has a t-stat. As far as I know, all boats/motors have t-stats.
 
I had a very similiar problem.
My 3.0L 4cyl engine had a problem with the carb just as U describe. It was in fact the choke itself causing this problem.
The way I went around it was:
The choke "thermostat" had scribe marks on it. Loosening up the set screw and twisting this "thermostat" would "manually" close the choke or open it depending upon which way U turned it. It was really a pain in the ass, although it would warm up and I'd slowly adjust this unit until she idled correctly.
After a season of frustration, (due to lack of $$$$$$), when we got ahead I had it fixed. Now that is a notch in my belt, and I've learned (the hard way) that boating is sometimes expensive. BUT, when the repair is done completely, and correctly it is a pleasure to go out.
 

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