7.4 hard start after sitting

[sming250r]

So just to start this is my first carbureted engine in anything.

After sitting a week it starts hard which I think has to do with the drain back issue. This isn’t too big of an issue starting off.

The other issue is that if I run for a while, get to full operating temp and shut off for more than say 15 minutes I have the same hard start issue. Maybe I’m not gifted in the start up process of this thing out I just need efi

Anyone tried that Holley sniper efi?

[Kate]

"hard start issue."

Can you describe what's happening? Slow crank or what? I'm guessing normal crank when it's been sitting, but hard to fire. Then slow crank (and hard to fire) after hot run.

Without more info, sounds like vapor lock. What are you doing with the throttle before and during crank?

[sming250r]

"hard start issue."

Can you describe what's happening? Slow crank or what? I'm guessing normal crank when it's been sitting, but hard to fire. Then slow crank (and hard to fire) after hot run.

Without more info, sounds like vapor lock. What are you doing with the throttle before and during crank?

Ok ya sorry. Should've included more info. Initial start up after been sitting for a few weeks it turns over quickly just long cranks. Usually give it a couple pumps with drive disengaged then crank. Crank for a few seconds approx 5-8 seconds let off start cranking again and start working throttle between full and half throttle. My thought process is thinking that its flooded..when I have small engines flooded I hold them wide open to over come that. Ive never had it start with no throttle input unless its been shut off for a few minutes like having someone get in the back of the boat.

Now the second issue where it hard starts after it has sat for more than 15 minutes or longer its basically the same issue. Seems to be cranking the same as it normally does. Normally it starts up quicker than the first issue but there are times where it could take three to four times of cranking with the same type of throttle input before it starts.

When this is going on am I better off with shorter cranks with no throttle input, longer cranks with more throttle input or some other combination of this?

Thanks for the help in advance.

[sming250r]

Thoughts on using a low volume low pressure electric fuel pump in line of the original lift pump?

[dustinm]

Your cold start is just fuel evaporating out of the carb, plus a little cold blooded. For that a few pumps of the throttle like your doing is normal. If you enrichen your carb to start right up when cold, when it warms up it will flood very easy.

Second sounds like vapor locking ie your gas is boiling out of the carb/lines. I used to run the fan an extra long time with my carb after it was hot and setting like this... that fuel vapor is still in the compartment and also it would bring cooler air in for the engine too. Modern gas is formulated for completely closed fuel systems used by fuel injection today... you may try different gas and eliminate ethanol too. What gas are you using??

[Kate]

"Should've included more info."

Sounds like you have two separate issues, both of which I've experienced (with the same set up).

At cold, you're flooding her. My fix: One or two small primes, from 12-11. Then at start, throttle at neutral or 11. Starts right up.

After running hot: Vapor lock. My fix: Slow down with blower on (thus cool down) while idling to anchor. (If really hot, open engine hatch for a bit.) Don't: Ride hard, then put away wet. (There are also thermal wraps for the gas line.) At start, same process as with cold. Starts right up.

[sming250r]

A little bit of an update. I borrowed a buddys muffs and tried a start last night. So it had been sitting approx 24 hours. After doing a little more digging I had thought that maybe I was flooding it to begin with as well. I did the couple primes and had it running in a couple revolutions. I did have the flame arrester off so I could see what the carb was doing as well. Which probably helped a little. The arrester wasn’t clogged but it looks like it could use a good cleaning. Can’t hurt anyways.

I think I agree with Vapor lock being the second issue as well. I think I need to be more liberal with the bilge blower and possibly open up the hatch if possible especially after longer sustained runs when I know I’m going to be shutting it off.

Inexperience with slight panic with it not firing right away I think are my biggest problem. Thank you guys for responding will update again after another trial run.

[dustinm]

One other thing you could try after the boat has set for a week, is to see when the throttle is pumped if at the same time you can see fuel squirting down the 2 closest barrels to you of the carb. This would also help identify cold start issue, if there is one. A carb boat is going to need a couple if not three shots of fuel to start(COLD).

[Kate]

Another issue to consider: Was the gas stabilized during winter storage?

[sming250r]

I haven’t thought about that. I purchased the boat after it had been in storage for the winter. It has half a tank in it when we first filled it up. Since then I’ve put a mix between 91 and 87 with no ethanol in it. Or so they said. If it wasn’t treated than hopefully I’m getting out of that older gas since I’ve put a couple fill ups in it.

Thanks for giving me ideas of stuff to look at and think about.

[Kate]

"Thanks for giving me ideas of stuff to look at and think about."

YW.

Here's another: Has the fuel/water separator been replaced recently? It's an easy DIY. (She might be suffering from fleas and ticks.)

[sming250r]

UPDATE. We spent the last week at loto and happy to report back that didn't have any starting issues the whole time down there. I was worried since temps were going to be over 100 each day. I think cleaning the flame arrestor helped some, but I think the main issue that was resolved was not flooding it with too much throttle input on my part. I thank you for the help.

[Kate]

Thanks for the update. Glad the tips helped.