Whats wrong with my boat?

[cstultz74]

I have a 2014 stingray. It has a mercruiser 4.3. 2 years ago the boat was running fine. In October, I had an accident and broke my back. I ended up not having it fully winterized. I just had the block drained and the boat wrapped. Anyhow, the next year, the boat sat. I physically wasn't able to use it. I just left it. I planned on using it this year. I took it out and it's not running right. I changed the battery. Changed the gas. Changed the fuel/water filter. It's still not running right. Here are the symptoms
Runs fine without a load (in neutral)
Runs fine in reverse.
Bogs down and doesn't go over 2000 RPMs in fwd gear
Any ideas? Prop? I can't get it into a shop because they're all too busy right now.

 

[Eric 3.7LX Alpha 1]

Bad gas and/or carb is buggered up is my guess. By changed the gas are you saying you pumped your tank empty and started fresh?

 

[cstultz74]

I ran it until it was dry and then put new gas in it. I did spray the crap out of the carb with carb cleaner. Every once in a while, it will take off and run okay. When I do put it in gear, I hear air releasing. Almost like it's a vacuum blowing.

 

[Rick Stephens]

I ran it until it was dry and then put new gas in it. I did spray the crap out of the carb with carb cleaner. Every once in a while, it will take off and run okay. When I do put it in gear, I hear air releasing. Almost like it's a vacuum blowing.

Spraying carb cleaner on your carb is as useful as pouring vodka on your hair when you want a drink. Doesn't do anything. Need to disassemble, clean everything and put a kit in it.

Other possibility is a vacuum leak. Might take an unlit propane torch and aim it around the intake manifold and base of carb while running to see if it changes RPMs .

 

[cstultz74]

If it were anything with the carb or gas... why would it run fine in reverse? Does it have to do with the load on the engine? There was evidence of some critters living in there. There could definitely be some gunk in it.

 

[Rick Stephens]

If it were anything with the carb or gas... why would it run fine in reverse? Does it have to do with the load on the engine? There was evidence of some critters living in there. There could definitely be some gunk in it.

Well, you got me there. No idea. I am never afraid to clean and kit a carburetor that has any kind of issues though. It is a worthwhile task on a carburetor that scarfed some crap.

 

[cstultz74]

I just ordered a kit. I'll clean it and see what that does. Fingers crossed. I'm hoping to avoid the spark plugs. They just seem like a pain in the butt to get to.

 

[tank1949]

If it were anything with the carb or gas... why would it run fine in reverse? Does it have to do with the load on the engine? There was evidence of some critters living in there. There could definitely be some gunk in it.

when do you put load on boat while in reverse???? It may be more serious. If you question winterization, do a compression test to achieve some peace of mind. Water inside crank case is another concern to investigate. If these are ok, then check plugs for crud and carb and fuel line for crud. There is a trick I learned decades ago on muscle cars that quad-jets. With throttle line disconnected, rev up engine and force you hand palm on top of butterflies until motor starts to stall. Manually work throttle. This causes a suction and may suck small crap out of carb into the combustion chambers. However, if you have time a money, rebuild carb after cycling good fuel through tank and fuel lines..

 

[cstultz74]

Thanks. I just tried running in reverse tonight. It seemed to run okay. The rpms went where they need to go. It wasn't limited.
I saw the trick with getting the carb to spit out junk by covering it. I'll try that next time I have a chance. Getting to plugs seems like a big pain. I ordered a carb rebuild kit. Hopefully it's something easy for now. I'll get a full tuneup next spring.

 

[jimmbo]

Thanks. I just tried running in reverse tonight. It seemed to run okay. The rpms went where they need to go. It wasn't limited.
I saw the trick with getting the carb to spit out junk by covering it. I'll try that next time I have a chance. Getting to plugs seems like a big pain. I ordered a carb rebuild kit. Hopefully it's something easy for now. I'll get a full tuneup next spring.

When you run an outboard or an I/O in Reverse, exhaust gas gets into the Prop Blades and unloads them, allowing the engine to rev up. You likely have Gum and Varnish in the Fuel Circuits. You could just close the choke, that will pull excessive fuel through the Main Nozzles if the RPM are above Idle, but really won't clear the Idle and Off-idle Circuits. It may have been a wee bit more effective to spray the carb Cleaner into the Fuel Bowl, but that usually just breaks piece of Varnish off to plug up the passage even more. The Carb has to come apart, and be properly cleaned, and some parts replaced and adjusted to spec.
It is possible that over the two seasons of being parked there has bee some deterioration of the Plug Wires, and corrosion under the Distributor Cap. Does it Produce a Good Spark(3/8") at all Cylinders?

 

[tpenfield]

When you say "you had the block drained" were the exhaust manifolds also drained?

 

[Scott06]

First guess would be as recommended carb strip down and rebuild.

Would also do a compression test to make sure no valves are hung up and engine is still in god shape .

Also sitting would not ignore the ignition system. Would check cap and rotor may have corroded. Verify you have good strong spark with a gap tester and you are getting ignition advance with a timing light

 

[cstultz74]

Got around to looking at this today. It really sucks that I cant get it in anywhere and nobody is returning my calls. Anyhow... I started to take the carburetor off today and didn't even make it beyond the first step. The brass fitting on fuel line is stripped and the line seems to be loose.
here is what it looks like
Loose and stripped fuel in line

 

[Rick Stephens]

You must use a line wrench on fuel fittings. And you also need a wrench on the filter housing into the carburetor to keep from twisting up the fuel line.

 

[cstultz74]

Well I'm glad I didn't go crazy trying to get it off. I stopped as soon as insaw it wasn't going to work

 

[Eric 3.7LX Alpha 1]

I think that big nut that is loose is either 1" or 1-1/8" but not positive. You can also use a big adjustable wrench with smooth jaws to hold back with, as you crack that brass nut loose. I agree with the line wrench for the brass nut, best tool for the job, I think that one is 5/8"

 

[cstultz74]

Actually found a boat repair shop that can take it in. Finally.