Boat Hard to Start After a Long Sit

[isaacs]

My boat is sometimes hard to start after it has been sitting in my driveway for a couple of weeks. Once I get it going (after lots of pumping and cranking) it runs and idles like new. If it sits for only a day or two I usually have no problem.

I should mention that the boat has a carburetor and I bought it new. I have never changed the spark plugs.

Any ideas? Thanks, Bob

 

[GA_Boater]

Gas in the carb is probably evaporating after a couple of weeks. The fix - Use the boat more often.

What boat do you have sitting in the driveway? Also what Mercruiser?

 

[tpenfield]

Gas might be draining back into the fuel tank . . . there should be a check valve at the tank fuel fitting. Maybe see if that is working properly or gummed up.

 

[Rick Stephens]

Electric fuel pump? Mechanical fuel pump.? Have you checked the anti-syphon valve?

I added a check valve between water separator and the fuel pump, resolved this issue for me. I believe fuel was draining back into tank leaving fuel lines and carb empty.

 

[Scott Danforth]

in addition, what is your ambient temperature? gas will evaporate faster out of the carburetors at higher temperatures.

 

[Scott Danforth]

BTW, after 19 years, you may want to change spark plugs, cap, rotor, and I would look at ordering a new 3-wire ignition module to have on hand when (not if) the ignition module in your distributor goes bad

 

[GA_Boater]

Sorry, Issacs. I missed your sig with the boat specs. This light font

 

[Scott06]

Basic tune up parts cap rotor plugs wires and ignition sensor are good ideas. My carb dries out too. The cranking is just to refill gas in the carb bowl , bump the starter 20 sec then pump it to set choke and let accelerator pump squirt some gas in. It will fire right up.

 

[Furbird]

Previous owner put a primer bulb on my boat. Few squeezes and it fires off in just a couple of seconds.

 

[isaacs]

Sorry, Issacs. I missed your sig with the boat specs. This light font

Yeah, they're hard to see. I'd add a picture to it but I can't figure out how.

 

[isaacs]

BTW, after 19 years, you may want to change spark plugs, cap, rotor, and I would look at ordering a new 3-wire ignition module to have on hand when (not if) the ignition module in your distributor goes bad

I change the cap and rotor regularly, I just changed the sensor in the distributor. Not sure what you mean by the three wire module. If you're referring to the Thunderbolt ignition, they're quite expensive--not sure I want to buy one "just in case".

 

[isaacs]

Thank you so much for all the replies, you've given me some good ideas. The boat is headed out for it's last ride today, then it will be covered for the winter.

It's an electric fuel pump; perhaps I'll switch the ignition on and off several times then give it a few good pumps before I even start cranking, we'll see what happens. In the spring it's getting new plugs.

 

[Scott Danforth]

the ignition module in the distributor or sensor as you mentioned. the new one is 3 wire vs the old one with 2-wire.

 

[isaacs]

the ignition module in the distributor or sensor as you mentioned. the new one is 3 wire vs the old one with 2-wire.

Got it! Yeah, it had an extra ground wire on it; I found a good spot to bolt it to.

 

[Rick Stephens]

It's an electric fuel pump; perhaps I'll switch the ignition on and off several times then give it a few good pumps before I even start cranking, we'll see what happens. In the spring it's getting new plugs.

Switching the ignition on and off doesn't do anything with a carbed engine. With fuel injection engines, turning the ignition on cycles the fuel pump and primes the system.

Carbed engine with electric fuel pump has two ways the fuel pump gets power - first is during cranking there is a wire from the starter that powers the pump. Once oil pressure comes up, there is an oil pressure switch that powers the fuel pump. The oil pressure switch is the main source of power for the pump. Lose oil pressure, pump quits - not soon enough to save your motor though. The purpose is a safety one to prevent the pump running when the engine isn't so fuel doesn't fill the bilge and cause the big boom.

First start of the season when I am dewinterizing, I cross power the purple/yel wire at the starter to power the fuel pump until the carb is filled up. That way I don't have to crank uselessly while waiting on the fuel pump to catch up.

 

[isaacs]

Switching the ignition on and off doesn't do anything with a carbed engine. With fuel injection engines, turning the ignition on cycles the fuel pump and primes the system.

Carbed engine with electric fuel pump has two ways the fuel pump gets power - first is during cranking there is a wire from the starter that powers the pump. Once oil pressure comes up, there is an oil pressure switch that powers the fuel pump. The oil pressure switch is the main source of power for the pump. Lose oil pressure, pump quits - not soon enough to save your motor though. The purpose is a safety one to prevent the pump running when the engine isn't so fuel doesn't fill the bilge and cause the big boom.

First start of the season when I am dewinterizing, I cross power the purple/yel wire at the starter to power the fuel pump until the carb is filled up. That way I don't have to crank uselessly while waiting on the fuel pump to catch up.

This is great info and it explains a lot. I can see what you're talking about by studying the wiring diagram. Now I understand why I have to do a lot of cranking after a long layup; a bit tough on the battery but it eventually starts every time!

 

[jakwi]

If you really want to know for sure you could spray a little starter fluid in the carb before you crank it the first time. If it immediately fires then evaporated gas is your issue, but if it doesn't you might have something else going on. I had a similar issue before I replaced my exhaust manifolds, and I found just a little bit of water where it wasn't supposed to be. After I changed them the hard start after a three week layup issue went away completely.

Anyway it's worth making sure.

 

[isaacs]

If you really want to know for sure you could spray a little starter fluid in the carb before you crank it the first time. If it immediately fires then evaporated gas is your issue, but if it doesn't you might have something else going on. I had a similar issue before I replaced my exhaust manifolds, and I found just a little bit of water where it wasn't supposed to be. After I changed them the hard start after a three week layup issue went away completely.

Anyway it's worth making sure.

Thanks, I'll give that a try but it may have to wait 'till next season.

 

[Kubaat3lover]

Switching the ignition on and off doesn't do anything with a carbed engine. With fuel injection engines, turning the ignition on cycles the fuel pump and primes the system.

Carbed engine with electric fuel pump has two ways the fuel pump gets power - first is during cranking there is a wire from the starter that powers the pump. Once oil pressure comes up, there is an oil pressure switch that powers the fuel pump. The oil pressure switch is the main source of power for the pump. Lose oil pressure, pump quits - not soon enough to save your motor though. The purpose is a safety one to prevent the pump running when the engine isn't so fuel doesn't fill the bilge and cause the big boom.

First start of the season when I am dewinterizing, I cross power the purple/yel wire at the starter to power the fuel pump until the carb is filled up. That way I don't have to crank uselessly while waiting on the fuel pump to catch up.

Hello Rick, where are these cables to cross them? thanks

 

[Rick Stephens]

You can connect red to purple/yellow. Purple yellow goes direct to the pump, red is from the battery. I do it right at the starter.