165 hp mercruiser, problem keeping it runnung

[falcon_lake_texas]

hello everyone. i have a 165 hp mercruiser. i have replaced the entire ignition system: coil, plugs, wires, points, condenser, dist. cap, rotor. i also installed a new starter and relays. then i replaced the original carb. with a reman from the auto parts store. the boat turns on when choked but turns off seconds later. can anyone please help solve this problem. thanks

 

[DukesFin]

Re: 165 hp mercruiser, problem keeping it runnung

Did you put an automotive carb in your boat? If so, please replace it with a marine carb or modify it for marine use.

Sounds like your re-manned carb isn't shooting fuel past the initial jet of starting. What is your "starting procedure" with the throttle?

What size/type carb are you running? Idle mixture screws adjusted correctly?

I'm having some carb issues myself, so these ideas are what first comes to my mind...

 

[falcon_lake_texas]

Re: 165 hp mercruiser, problem keeping it runnung

hello there. apparently the 165 hp mercruiser engine is exactly the same as a 4.1l 250ci gm, early 70's. of course they had to modify it somewhat. like the saying goes, "why re-invent the wheel". you could find replacement parts at any local auto parts store. use a 1970 chevy c10 4.1l 250 4x2 (or take the original part in and they cross reference the part number.) there are the same exact engine parts however, i do believe the camshaft and maybe one other thing is different. like i said, i've done a complete tune up with parts from the auto parts store. they are exactly the same parts. the original carb that was on was so clogged up it wouldn't even choke. a new carb ran me 150 bucks. so i ordered it and installed and waalaa, it turned on. now the engine starts but won't stay on. i don't know where to look from here. is it a timing issue? or does the carb need adjusting? how can i tell?

 

[crs5357]

Re: 165 hp mercruiser, problem keeping it runnung

I bought a Sierra Reman carb for my 165 and it was just a little over $200.

I have replaced all those things in my 165 including the fuel tank, but have
converted to Pertronix ignition and thus put my spark plug gap now at .040".

I would recommend it.

Fuel, Air, Spark. When things go south, I keep reminding myself of this.

A great engine-165.

 

[95yj]

Re: 165 hp mercruiser, problem keeping it runnung

Falcon, the engine is exactly the same as a car engine. . . BUT it's been marinized so as not to explode. Take your automotive carb. If the floats stick, gas will dump out on top of your engine in a closed compartment and all those fumes will accumulate until a spark from your automotive distributor cap make the whole back of your boat disapear. The marine carb is set up so that any fuel leakage will leak down inside the intake manifold and will be consumed by the motor.

Using auto parts on a boat is DANGEROUS! Just do some browsing here and you'll find plenty of what is different between the two.

 

[Haut Medoc]

Re: 165 hp mercruiser, problem keeping it runnung

Falcon, the engine is exactly the same as a car engine. . . BUT it's been marinized so as not to explode. Take your automotive carb. If the floats stick, gas will dump out on top of your engine in a closed compartment and all those fumes will accumulate until a spark from your automotive distributor cap make the whole back of your boat disapear. The marine carb is set up so that any fuel leakage will leak down inside the intake manifold and will be consumed by the motor.

Using auto parts on a boat is DANGEROUS! Just do some browsing here and you'll find plenty of what is different between the two.

Not to mention illegal.....

 

[95yj]

Re: 165 hp mercruiser, problem keeping it runnung

Makes your insurance company happy. Once they find automotive parts in the wreckage, they don't have to buy you a new boat.

 

[MikDee]

Re: 165 hp mercruiser, problem keeping it runnung

The carb for a 165hp mercruiser is a 2bbl carb, not an automotive 1bbl carb like all the Chevy Nova's like I had,,, that, and a better cam is what gives it 165hp, over 150hp in the car. I had a 165hp Mercruiser I rebuilt in an old 18' Wellcrat Airslot, one of the best motors, and rough water boats I think ever made, and that boat could do 45.

 

[falcon_lake_texas]

Re: 165 hp mercruiser, problem keeping it runnung

MikDee. the carb that was replaced was a 2 barrel, not a single.

Haut Medoc- "The marine carb is set up so that any fuel leakage will leak down inside the intake manifold and will be consumed by the motor." ---it still does. nothing has changed. its the exact same. i took the original carb in and they cross reference the numbers. its a 2-25 carb for 4.1l. i compared them and the only difference is one works and is reman, and one doesn't.

 

[95yj]

Re: 165 hp mercruiser, problem keeping it runnung

That means you bought a marine carb from the auto parts store. The point being auto parts are not the same as marine parts. Make sure you get the marine parts when replacing anything.

 

[ziggy]

Re: 165 hp mercruiser, problem keeping it runnung

what year is yer 165?

have ya tested fuel pump pressure. should most likely be 3.5-4.5 psi.

ya got a new fuel pump filter + cleaned out the inlet screen at the carb i assume.

have ya got dwell at 31-34*, timeing at 6* btdc...

most likely, priliminary carb idle set screw at 1 1/4 turns out from lightly seated.

its a 2-25 carb

i don't know what that is. my carb is designated a 2GC. saw a pic on here the other day that a fella with a 165 had what looked like a bc carbureter. a one barrel. the 2 165s i've had both had the 2GC on them.

not to jump on the bandwagon. but yes. do use marine parts. specified at the auto parts store. or just shop at the mercruiser store and for sure get marine parts.

If the floats stick, gas will dump out on top of your engine in a closed compartment and all those fumes will accumulate until a spark from your automotive distributor cap make the whole back of your boat disapear. The marine carb is set up so that any fuel leakage will leak down inside the intake manifold and will be consumed by the motor.

how is this accomplished?

 

[ParallaxBill]

Re: 165 hp mercruiser, problem keeping it runnung

Mine also has a marine 2GC. Great carbs on autos, just as good on boats.

 

[CharlieB]

Re: 165 hp mercruiser, problem keeping it runnung

Getting back to your original post;

turns on and dies seconds later

Are you saying that it is a manual choke and dies when you turn the choke off?

I am wondering if you have an ignition problem, sparks OK while cranking, initially fires,starts, and immediately dies, no ignition switch voltage to the coil.

GM points style ignitions have two wires to the + side of the ignition coil. One, a 'resistor' wire supplies a reduced voltage for running off of the ignition switch, the second wire comes off a small terminal of the starter solenoid to supply a full 12 volts during cranking/starting only.

Failure of the second makes motors hard to start.

Failure of the ignition side will fire/start and immediately die.

 

[falcon_lake_texas]

Re: 165 hp mercruiser, problem keeping it runnung

Hello everyone again. i replaced the mech. fuel pump. i think the original was weak therefore turned off seconds later. now the engine does run without dying. what a huge difference