Difficulty Starting Engine?

[ajinid]

I bought a used boat which had great difficulty starting and running smoothly. I had the carb rebuilt which now has helped the engine run smoothly, but it will not a start unless I push the throttle forward just the right amount... EVEN after it has run for 30 minutes and is plenty warm. This is quite annoying as it usually takes multiple attempts to get it started. The plugs and compression in each cylinder are good. Ignition system/coil coil seem to work fine. Any ideas?

1996 5.8L 351W engine, 4bbl Holly carb, volov DP outdrive.

Thanks for any help you can offer, AJ

 

[havasuboatman]

Re: Difficulty Starting Engine?

How far is "just the right ammount"?

 

[ajinid]

Re: Difficulty Starting Engine?

I would say "Just the right amount" is about the half way point between idle and 1/4-1/3 throttle.

 

[ErieRon]

Re: Difficulty Starting Engine?

I don't think it's that unusual to have to pump your throttle on a carb'd engine. Much like the old days with cars before fuel injection. If it seems excessive, probably a choke issue or time to rebuild your carb.

 

[havasuboatman]

Re: Difficulty Starting Engine?

That's how I start my boat. Two pumps and then a little throttle. When it's cold, as much as 1/4 throttle. Just be aware that when the motor catches, you will need to back it off a bit.
Does it do this when the engine is all warmed up, too?

 

[Don S]

Re: Difficulty Starting Engine?

It's a carb, not EFI like your car. Takes some a little thought and attention to start a carbed engine and keep it running.

 

[ajinid]

Re: Difficulty Starting Engine?

Ron,

I did just had the carb rebuilt at a professional shop. And I agree that a some pumping of the throttle is needed with a carbed engine. I had a 302 that needed some pumping when it was cold, but once it was warm, it would always start right up from the neutral position.

This 351 though is a pain to start. Giving it few pumps won't do it. I actually have to hit the gear release button and hold the throttle in a forward position in just the right spot to start it, even if its been running a for a while and is warm. Its not super easy to hit the sweet spot for starting either. There has to be something up, I figured a complete carb rebuild would have solved it, but it didn't. I am just wondering if something else might be causing this symptom?

AJ

 

[Don S]

Re: Difficulty Starting Engine?

Since we posted at the same time, when was the last full tuneup and compression check? More to them than just the carb.

 

[ajinid]

Re: Difficulty Starting Engine?

Compression check and tune-up was done at the same time the rebuilt carb was installed (last week). He mentioned he had to push the throttle forward to help it get started, made it sound like it was not abnormal. He thought it might be because the weather was cold (60 degrees). When I got the boat home I tested it myself and figured something else is wrong since it still won't start easily, even when the engine is warm.

AJ

 

[Don S]

Re: Difficulty Starting Engine?

Here is the difficult part of your problem. Was the tunup done correctly, was the compression check done correctly (and what were the results) and was the carb rebuilt correctly and was it rebuildable to begin with.

I get jobs in the shop all the time that say it was all done, only to find it was done completely wrong or had faulty parts.
You could have anything from a misadjusted choke to a dead cylinder causing your problem. Throttle possition is not a way of narrowing it down, Sorry,

 

[grahamh]

Re: Difficulty Starting Engine?

Is the choke set up properly? Maybe it was never adjusted after the carb was rebuilt, adjusting chokes is kind of a pain, since once the engine is hot you can't adjust the choke.

 

[ErieRon]

Re: Difficulty Starting Engine?

I agree with Don & Graham...I do all my own tune up & carb stuff now just so I know it's right. Don't get me wrong, there are things I can't do and don't fully understand, but the stuff that just takes attention to detail I tend to learn and do on my own. It really sounds like choke to me, but Don certainly is the authority here. If you don't have the tools, diagnostic equipment and know-how, I would take it back to whoever worked on it last and see what they have to say.

 

[havasuboatman]

Re: Difficulty Starting Engine?

I agree with Don & Graham...I do all my own tune up & carb stuff now just so I know it's right. Don't get me wrong, there are things I can't do and don't fully understand, but the stuff that just takes attention to detail I tend to learn and do on my own. It really sounds like choke to me, but Don certainly is the authority here. If you don't have the tools, diagnostic equipment and know-how, I would take it back to whoever worked on it last and see what they have to say.

Exactly, Isn't that why you took it to them in the first place?

 

[bigskiohio]

Re: Difficulty Starting Engine?

make sure choke is adjusted right and mine takes a little throttle to start when warm but i have to idle it down as soon as it starts and goes to idle, my idle is a little low now so will re adjust in spring.

 

[ajinid]

Re: Difficulty Starting Engine?

Thanks for all the input. I'll take it back and get it checked out, hopefully its an easy fix.

 

[rebars1]

Re: Difficulty Starting Engine?

Is the idle speed set correctly? What RPM's is it running at? Do you have current to the electric choke?

 

[26aftcab454]

Re: Difficulty Starting Engine?

I have a 1996 carb-ed 454 and was told when I bought it to cold start this way:
1- disengage from gear
2- pump throttle WOT once or twice
3- push throttle to about 1/4 open
4- start

if its been sitting up a week or longer it takes 2 or 3 cranks

if warm I just turn the key and it fires right up.

not long ago it would take 2 or 3 minutes to crank when cold. I replaced the fuel pump and distributor cap[ 7of the spark lugs on top of the cap were shinney like a new penny and the # 5 was brown ] and it went back to starting right up and running on all 8 cyl.
I my be slow but I'm persistant!
good luck-Joe