4.3 Mercruiser LX Hard to Start when warm

[Trooper583]

Hey guys, thanks for taking the time to look at my post. These forums have saved me countless dollars and hours working on my own boat. Here's another one for you experts out there.

My boat - 1995 Rinker 212 OB 4.3L LX with Thunderbolt Ignition.
Engine # 0F269336
Drive # 0F523351
Transom # 0F545581

The best I can tell...It has a Weber 4 barrel carb on it (9600S 3194 - stamped on front)

I bought the boat about a year ago and with it being my first vessel, I have learned a lot of about these things. I have replaced the fuel pump, starter and countless other repair items.

The guy I bought the boat from told me that when he purchased it, the engine was blown so he ordered a new Jasper short block and swapped everything over. Outside of a few hiccups here and there over the past year, it runs really, really well.

Ok, on to the issue...When I back the boat into the water at the ramp, I pump the throttle twice and literally, BUMP the key and it starts amazingly fast for being cold. after it starts almost instantaneously, it never dies, and will come on up to operating temperature. After my wife and I drive over to our favorite bay about 2 miles away, we usually sit / swim for around an hour. When I go to start it to leave, it take forever to start as I have to turn it over and over and over. It finally stumbles to a start and runs fine from there on out.

Now, it seems like the longer it sits, the harder it gets to start. This sort of leads me to believe that perhaps its boiling the fuel out of the carb.

Also, I have absolutely no other fuel delivery symptoms on the boat.

Sorry for the long winded post!!! Thanks for the help.

 

[dingdongs]

Re: 4.3 Mercruiser LX Hard to Start when warm

let it tickover for a few minutes before turning it off and lift the engine hatch to try and get some cool air circulating and see if it improves.use the better quality fuel as previous postings have had problems with the cheaper stuff.

 

[90stingray]

Re: 4.3 Mercruiser LX Hard to Start when warm

Mine did the same thing... I have a 2 bbl mercarb. I installed a spring loaded needle and seat. Cured the problem! Might want to pull flame arrestor and see if fuel is dribbling in the throat. Could be your problem too. Goodluck!

 

[dubs283]

Re: 4.3 Mercruiser LX Hard to Start when warm

pull flame arrestor and see if fuel is dribbling in the throat.

yep

webers are known for being "thirsty" and tend to load up a lot easier than q-jets, look for fuel dripping down the throats upon shutdown - sounds like your engine is flooding and taking a bit to clear out upon warm start

to clear flood, put the throttle at WOT when cranking and leave it there until the engine fires, then bring back to an idle - the throttle plates at WOT will help clear out the engine by providing lots of air

 

[Trooper583]

Re: 4.3 Mercruiser LX Hard to Start when warm

Thanks for all the info so far... I checked on a rebuild kit for the carb today and it was priced at $83.00. My mechanic said that a good carb overhaul would probably be a good idea and fix the problem as well. your thoughts?

 

[Bondo]

Re: 4.3 Mercruiser LX Hard to Start when warm

Thanks for all the info so far... I checked on a rebuild kit for the carb today and it was priced at $83.00. My mechanic said that a good carb overhaul would probably be a good idea and fix the problem as well. your thoughts?

Ayuh,... The Weber is a carbon copy of the Edlebrock performer series,...

The Edlebrock parts are more plentiful, 'n Cheaper than Merc listed parts...

These are 1 thing where avoidin' the Oem makes sense, 'n using aftermarket stuff is Much Better......

 

[Trooper583]

Re: 4.3 Mercruiser LX Hard to Start when warm

Thanks for that info....I'm looking forward to getting the carb rebuilt and seeing what, if anything else changes performance wise. As always, once I get the job done I'll post the results here. I know that doing that will help those that have this problem later.

 

[Trooper583]

Re: 4.3 Mercruiser LX Hard to Start when warm

ok...update, I went out for a few hours today. I didn't get a chance to look at my carb while we were sitting but I did do one other thing.


While turning the engine over I rolled the throttle forward to WOT and I did get a MUCH quicker start while warm. I'm sure this symptom is indicative of something. Your thoughts?

 

[dubs283]

Re: 4.3 Mercruiser LX Hard to Start when warm

While turning the engine over I rolled the throttle forward to WOT and I did get a MUCH quicker start while warm. I'm sure this symptom is indicative of something. Your thoughts?

uh...yeah,

same as my previous post, the carb is flooding out the engine upon warm shutdown

re-build the carb

 

[Trooper583]

Re: 4.3 Mercruiser LX Hard to Start when warm

Oops, sorry about that Dubs, I forgot that you had already mentioned that in an earlier post. Since you seem to know a lot about carbs...Should I just get the rebuild kit from my local parts store ($82.00) or could I get a Edlebrock performer series rebuild kit?