Harder to start when hot....

[KermieB]

I have a '90 Sea Ray 180 BR, 4.3 I/O. This boat has a engine compartment that is somewhat confined. There's not a lot of extra room under the engine cover. The first time I start the engine when I get to the lake, it fires up on about a half a rotation... bam. But as the day goes, and I get a lot of heat build up in the engine compartment it gets harder and harder to start the engine. I'm contributing this to a lack of fresh oxygen in the compartment, and I've tried leaving the blower on while I'm driving and while sitting, but so far nothing helps. I live in South Carolina and the temps have been in the high 90's, and high humidity.

I'm thinking about installing a 12v fan of some sort to better ventilate or maybe a grille of some sort, but before I do all of this.....has anybody else had this problem? Is there a better way? and Is heat actually the reason that it's harder to start? I bought the boat late last year, and this is the first hot season I've experienced.

 

[cr2k]

Re: Harder to start when hot....

Is your starter dragging? Slow turn over?

Gas boiling over when you shout it off?
You carb could be in need of a rebuild too.

May be time for a tune up?

Several things can contribute to this but I doubt lack of O2 is one of them.

Once you shut it off after it has been run long enough to present this problem pull the cover and the flame arrester and look in the carb and see if it full of vapors of if fuel is running in to it.

 

[Summer Fun]

Re: Harder to start when hot....

I always let my engines idle for 5mins before I shut them down.
This helps cool everything down in the engine bays.
I also run my blowers full-time when the engines are running.

 

[Silvertip]

Re: Harder to start when hot....

People are so in a rut with turn-key starting on their cars they forget that a carbureted boat engine has a shift disconnect (fast idle) provision. Use it on a hot engine. The engine needs an open throttle when hot. You might also check to make sure the choke is not closing even after a brief stop. If adjustment is necessary, DO NOT do it on a hot engine. Choke adjustment must always be done on a stone cold engine.

 

[SeanT]

Re: Harder to start when hot....

I'm curious what you mean by that Silvertip? Could you explain a bit more?

Are you suggesting that we should be providing throttle to our carbureted engines when starting, even when hot?

 

[MTribe08]

Re: Harder to start when hot....

I'm curious what you mean by that Silvertip? Could you explain a bit more?

Are you suggesting that we should be providing throttle to our carbureted engines when starting, even when hot?

Just thought I would add to what silvertip said. I posted up the same thread a few weeks back. I too have the same characteristics with my boat. 5.7l merc. 4bbl Carter carb.

Starts nice and easy cold, but not so much when hot. I used to pump the throttle a bit when hot starting and that didn't seem to help much. Then another poster reccomended that I crack the throttle just a bit and leave it there, don't pump it. Gives the engine more air on start up. Worked great! Now it fires within a second or 2. Pumping, just made the problem worse.

 

[HotKetchup]

Re: Harder to start when hot....

Good info! My 5.7l 2bbl does the same thing. I figured out on my own about disconnecting and giving it a little throttle to start. works like a charm. Good to hear this is normal.

 

[dirtdiver]

Re: Harder to start when hot....

I have an 89, when its hot I have to put it at about 3/4 throttle and as soon as it starts pull it back to idle (all in netural). Works like a charm. Had a guy on at a gas pump dock tell me that one. Thats one thing I like about boating, there are so many nice people willing to help you.

 

[windsors03cobra]

Re: Harder to start when hot....

So weird, my ole straight six fire right up in the idle position no matter if its been sitting a minute or an hour. I do set the throttle up for cold starts after I pump it 3 times and it normally fires right up.
I do have to hold my snowmobiles Suzuki 3 lunger throttle open a piece to start when hot. If I do not it might take 6 pulls to start. If I hold throttle and pull, it lights right off. I release the throttle as soon as it starts.

Must just be an overly rich mix thats gettign sucked in and it needs some air to make fire.
Fuel injection is sweet, the simplicity of a carb is nice too.

 

[MTribe08]

Re: Harder to start when hot....

Here was my thread on the subject. It was described to me as "heat soak" that happens when you shut down the engine and its really hot in that engine compartment. Basically forces fuel past the valve and puts the engine a mildly "flooded" state. Just needs a bit more air to fire off. Like I said earlier..pumping the throttle only makes it worse by dumping more fuel into an already flooded situation.
http://forums.iboats.com/showthread.php?t=402612

I don't need 3/4 of throttle..maybe an 1/8. Just enough to crack it open and let more air in.

 

[180shabah]

Re: Harder to start when hot....

Not trying to start ethanol bashing here, but it is much more "common" now than it used to be - "boil point" is lower...

 

[air2raley]

Re: Harder to start when hot....

I have an 89 Searay bowrider with these similar symptons. I did what you suggested and fuel is entering the carb and subsequently flooding. It never use to do this. Your statement regarding the lower pump has me intrigued. I haven't replaced it in 10 years and there are other symptons (hot idling) that would indicate it needs replacing. How is the lower impeller replated to the flooding of the engine? Is it causing the engine to overheat and boiling the fuel out of the carb? My carb is a two barrel

 

[180shabah]

Re: Harder to start when hot....

I have an 89 Searay bowrider with these similar symptons. I did what you suggested and fuel is entering the carb and subsequently flooding. It never use to do this. Your statement regarding the lower pump has me intrigued. I haven't replaced it in 10 years and there are other symptons (hot idling) that would indicate it needs replacing. How is the lower impeller replated to the flooding of the engine? Is it causing the engine to overheat and boiling the fuel out of the carb? My carb is a two barrel

Sounds klike you may have multiple questions/issues.

You need to start a new thread with all the details rather than tack on to someone elses - everybody just gets confused and nobody gets the help they need.

 

[DaveMac]

Re: Harder to start when hot....

First Post! Hope this helps...
Check your timing, sometimes the lock nut for the distributor loosens a bit and advances itself (damn chevys). Slow cranking when hot can just be that the timing is too far advanced. Check the vacuum/mechanical advance springs in the distributor too while you're at it.

Just my two cents, could be an easy fix. Timing is everything.

Cheers

-Dave