7.4 merc won't start after winter storage

[timharper89]

It comes out because the gas expands in the heat. Only way to stop it is don't fill it so full

What annoy in the winter? Isn't it recommended to keep the tank full to avoid condensation? Or empty, but i have a 75 gallon tank that would be difficult to time correctly for an empty tank.

Fed Regs says the fuel tank sender and fittings must be accessible. I had a 1995 rinker 232 and mine was same way, lucky for me but I never needed to get to.

Hopefully i don't need too either.

Right now lets hope its just bad gas or fuel pump.

shouldn't be gas since i put stabilizer and fresh fuel in the fall.

Disconnect the rubber fuel line at the filter. Get another piece of fuel line and a gas can. Connect fuel line to filter housing and stick other end in the gas can. Fill the filter full of gas and then try to crank it

this is what i was going to do if starting gas in the carb failed

Wear safety glasses

Oops...I know better

 

[San_Diego_SeaRay]

Got it started by spraying gas in the intake with a spray bottle. Ran beautifully for 10 minutes until I turned it off. Accelerator pump maybe? Carb need rebuilt?

IMO the fact it ran for 10 mins is a solid indication that everything from the gas tank to the carb is working properly. I'd focus on the carb at this point.

Even though my accelerator pump doesn't work, after I get it started and it's warmed up the boat starts up like a champ; no problems whatsoever.

I bet if you tried to restart your boat right now, it would fire right up.

Lastly, I hope you have it on water muffs. Otherwise, you're looking at a new impellar at a minimum.

 

[Bt Doctur]

did you ever check the oil level inside the pump body where it bolts up to the water pump

 

[timharper89]

did you ever check the oil level inside the pump body where it bolts up to the water pump

The fuel pump has oil? No I did not check that.

 

[alldodge]

Hope it was just a fluke

 

[tpenfield]

Perhaps that was water standing in the intake? Not sure if you smelled gasoline while doing all the cranking.

Rebuild the carb would be a good thing. . . or just get a new one.

with any no-start situation it is back to the basics . . .

Compression, Spark, Fuel.

It sounds like you didn't have fuel getting to the cylinders. As I recall my carb 454 was a bit difficult to start at the beginning of the season or if it had sat for a while. It seemed that my anti-siphon valve was a bit leaky and the fuel would drain down. Took a bit of cranking to get it re-primed.

 

[timharper89]

Hope it was just a fluke

Me too. I might rebuild the carb anyway just to be sure. Is it possible the fluid in the intake was the remnants of fogging oil or something? It definitely smelled similar to gas but a little different. I wondered about that

 

[timharper89]

IMO the fact it ran for 10 mins is a solid indication that everything from the gas tank to the carb is working properly. I'd focus on the carb at this point.

This was my assumption.

Even though my accelerator pump doesn't work, after I get it started and it's warmed up the boat starts up like a champ; no problems whatsoever.

I think I will order a rebuild kit. It can't hurt.. unless I mess something up

I bet if you tried to restart your boat right now, it would fire right up.

Yeah we did it again, and that's exactly what happened

Lastly, I hope you have it on water muffs. Otherwise, you're looking at a new impellar at a minimum.

Uh yes. Almost forgot though

 

[Grub54891]

On the picture of your fuel connector at the anti syphon valve looks to missing a hose clamp. Usually there are two clamps.

 

[cyclops222]

If as soon as you crank the starter motor. That big chokeplate swings WIDE OPEN or more than a 1/4" to 3/8" open. It will cause a LEAN COLD hard to start mixture. If the idle speed and idle mixture have been set with a warmed up engine ? The engine may be too lean and slow to start when cold.
lots of tweeks to get a engine starting and idling when cold.
What state are you and the boat in ?
DO NOT REBUILD the carburetor. It is fine when warm. Lets get the choke system correctly set up.

 

[04fxdwgi25]

Fuel pump sump lube:

 

[Grub54891]

Fuel pump sump lube:
View attachment 408315

I dislike those pumps myself. Had one customer's boat and it quit while moving it from the slip, windy day. Lucky people were around to help with avoiding squishing other boats at the docks and getting it back to the slip. Belt broke. That little belt works hard running the fuel pump and seawater pump. Also seen a few that went south from lack of maintiance. People don't know about servicing them. Don't know what Mercury was thinking when they designed them.

 

[Lou C]

Agreed that's a crazy design. Would have been better with a crank mounted impeller and normal fuel pump!

 

[04fxdwgi25]

Agreed that's a crazy design. Would have been better with a crank mounted impeller and normal fuel pump!

You are right, but the later model Gen GM motors don't have a fuel pump boss / drive, as everything went to electric fuel pumps in the auto world.

 

[timharper89]

Fuel pump sump lube:
View attachment 408315

Interesting. I will check that. Thanks.

 

[timharper89]

So I took it out on the water last weekend, and had the same problem with not wanting to start. Gave it 5-6 pumps on the throttle and cranked for about a minute in 5-10 second intervals with no luck. A couple squirts of fuel in the carb and it fired right up with no issues at all. Ran perfectly for 15 miles up the lake. Sat for about an hour to an hour and a half and took about 15 - 20 seconds to start up. Ran perfectly back to the dock. Choke not properly set or what might cause this issue? I was wondering if maybe the carb bowl is emptying over time or something? I don't really know, but once it gets that initial fuel it runs beautifully aside from the throttle cable not resetting all the way back, causing a high idle until I open the hatch and pull it back to idle. I could also use some tips on how to correct that as well. I will start a different thread regarding the clunking from the rear during tight turns after replacing the gimbal bearing this spring.

 

[alldodge]

A couple squirts of fuel in the carb and it fired right up with no issues at all

You are giving it gas by hand then weak pump or restriction in the line, otherwise Initial start is most likely fuel is evaporating or leaking out, and chock not set correctly.

Second start carb not adjusted correctly or it's leaking fuel

Had a 454 with AFB carb that after sitting it would take some cranking just to refill the bowl. I would crank it for about 10 seconds before even pumping the throttle because I knew the carb was empty.

When it sat for a hour or so I just crank without any pumping and it took about 5 seconds to start

 

[ESGWheel]

In reading thru this thread, it appears that checking the working of the accelerator pump has not been done. If true, then do this simple test:

1. Let the boat sit for a day or more… i.e. the same condition for when you experience a no start unless you spray gas into the carb but do not try to start it.
2. Instead remove the spark arrestor and with your finger fully open the choke plate (it will move open without and damage to the mechanism).
3. Using a flashlight look down the throat on the same side as the choke plate and have a buddy move the throttle to fully open in a nice smooth stroke. Come back to idle and repeat two more times. Again, the engine is NOT running, no reason to even have the key in the ign.

If you do not see gas squirting into each of those 2 barrels (a small stream like coming out of a syringe) for each stroke then one of two possibilities:

• accelerator pump is not working and thus need to rebuild the carb
• your carb is leaking fuel somehow and thus would start by rebuilding the carb and looking for issues (like a crack).

To determine which, do this immediately following the above test if there was no squirting.

• Start up the engine with your trick of spraying gas down the carb, let it run for a few minutes at idle. Then shut down and repeat the first test.
• Now if see a squirt, accelerator pump working, and your carb is leaking its gas somehow. If no squirt, then the accelerator pump is bad.

If during the first test you did get 3 good squirts, then I need to think about it more. Please post results of test(s). Thanks.

 

[ESGWheel]

Oh regarding the non-return to idle. Here is an older thread that may help, link.