I have a comp Mercruiser 5.7 motor ......carbuerator is getting no gas.....I checked filter and not clogged ....I then checked to see if Pump is working and it is.....the boat has been sitting for 4 or 5 summers but I did start it last summer with no problems. My guess is the jets are clogged. when I pour gas in carbuerator it starts right up.......What do u suggest ? Is their a cleaner that will unclog jets. any help is appreciated.
Make (of engine): 350 Mercruiser
Model (of engine): unknown
checked filter,pump is working,water seperator clean, I pour gas in carb and it starts right up.
When you say pump is working. Did you pull the fuel line off the the carb, and crank the engine over, and see fuel comming out of it?
Also, is the fuel in the boats tank 4 or 5 years old as well?
yes I pulled fuel line off carb and cranked over n saw fuel coming out.
and yes the fuel is 4 to 5 yrs old.
Gotcha so far.
That fuel is not going to be any good, and you are going to have to drain/pump the tank out. Thats step one. Now that might or might not be the only problem. You can do everything all at once and just be done with it, or do it step by step and trying the boat each time. But realistically here is what needs to be done. And you want to do things in this order to be time and cost effective.
1. Compression test. - Engines that sit have rust that builds up in the cylinders. When you go to crank the engine over, that rust gets blown out. Each time compression goes down just a little bit. But once it gets down to low, the engine is no longer usable. For results you need 100psi as a bare minimum on all cylinders. With all cylinders being withing 15% of eachother. You want to start with this before you throw any real money at the boat. If compression is no good, it does not matter what you do, the engine will never run correctly. If compression is good, then the engine will run once you take care of the laundry list.
If compression is good, then the next steps are all a go, and the engine will run.
2. Pump out of the fuel, and replacing it with new fuel
3. Full engine tune up. Cap, rotor, wires, plugs, all fuel filters
4. Rebuild the carb. Engines that sit always have carburetor issues. The fuel inside of the fuel bowl portion evaporates, and leaves behind a varnish type goo, this clogs the internal fuel an air jets on the engine.
That is what needs to be done here, and in that order. But start with the compression test first. You want to see if the engine is a runner or not first before throwing 1 dime that you do not have to into the boat.
Feel free to reply back with any questions
Degree in Marine Technology. Gas and diesel marine mechanic.