1976 22' Starcraft Islander Rebuild

[jasoutside]

So I am having cold start problem - lots of turn, turn, turn, turn, and hard to fire.

Aaaaaaand, it appears I have a little different problem going on here than I initially thought. I may have a lack of fuel, not necessarily a choke deal.

So, if you are a carb expert type guy (I am not) take a look at this video, if you expand it to full screen on youtube you can see a little better....

Normally I pump the throttle at the helm about 1/3 of the way, two times then advance it just a little for a cold start.

Here on the video I actually pump the throttle 6 times just about the same stroke that I might normally at the helm and I only get just a dribble. Then I pump it a FULL stroke three times to get a decent stream of fuel.

So tell me, that little dribble coming out on my initial throttle pump, is that my problem?

Or, should I be going FULL strokes on the throttle at cold start?

Advice?

 

[Patfromny]

It sure looks like you need to rebuild the accelerator pump. It looked like there wasn't even a steady stream when you full throttled it. The pump is under that arm on the bottom left. You see the arm depressing the pump when you pull back on the throttle. Sorry to say it but looks like a carb rebuild is in order buddy. Maybe you can find one locally. It looks like a standard Q-jet. 680 cfm maybe. If so it is an awfully common carb. You should be getting a steady stream when pulling the throttle back.

 

[Grandad]

Hi Jas. Not an expert but I'm old enough to remember putting new kits in carburetors. As you work the throttle lever, you're also working an "accelerator" piston that's supposed to squirt raw fuel into the throat of the carb. I don't see that happening in the video. It's a typical problem with these carbs. I think that's a Rochester carb. The piston is on that little rod that you see being forced downward by a second link. The piston has a flare on it to fit the little cylinder into which it's guided. It used to be leather which not only wears out but can dry out when not in gasoline. - Grandad

 

[dozerII]

Yes that little dribble is the problem, your not getting that rich prime to fire on, I always go with 2-3 full wide open strokes of the throttle prior to a cold start. Jason can you do another video after it has run so we can see the streams of gas the Accelerator pump id giving you? Rochester carbs really don't like ethanol blend fuels, if it sits in them it eats the bottom of the fuel chamber out where the welch plugs are, allowing the fuel to leak out thus making cold start hard till the pump fills the carb back up.

 

[jasoutside]

It sure looks like you need to rebuild the accelerator pump. It looked like there wasn't even a steady stream when you full throttled it.

Yup, you are right, a little better than a dribble really.

piston that's supposed to squirt raw fuel into the throat of the carb. I don't see that happening in the video.

Yep, me neither.

Jason can you do another video after it has run so we can see the streams of gas the Accelerator pump id giving you?

May engine has no power at the moment. I started pulling all my wires to move the batts back next to the doghouse right after I shot that video.



OK guys, I'm not surprised that this carb needs a rebuild. It was filthy dirty. I cleaned it up as best I could but even a clean carb that's wore out doesn't work all that well.

Like the V6 carb swap I did, I'm not super interested in rebuilding this one. So, recommendations?

Should I go back with a rebuilt Rochester Quadrajet? Or I'm reading an Edelbrock 1409 might be a good route to go (though I can't figure out if my intake will work or not with it). Should I stick with manifold choke or upgrade to an electric choke setup? Happy to hear your advice here guys.

 

[Watermann]

If your accelerator pump was bad you wouldn't of had much fun that day out on the water let alone go over 40. I think the motor would've stumbled all over itself and couldn't even get on a plane. I have a a QJ on my V6 too and as I mentioned I have to stroke mine WOT twice and slightly advance the throttle to have a good cold start. I upgraded from the old stove pipe to electric choke and the start sequence remained the same.

The carb is most likely having some leak down issues after sitting and looses it's fuel pressure and that's why it's not shooting fuel into the throat days later when stroking the throttle. That's either a symptom of a problem or just the way these carbs are since mine needs the double pump to get going.

It's funny though because if I don't do that sequence just right it becomes a bear to start too. Not enough fuel it won't start when lean, give it more fuel and it won't start being too rich. If you're up for a carb switch then I would go to the 1409 like you mentioned.

 

[jasoutside]

If you're up for a carb switch then I would go to the 1409 like you mentioned.

Well, after some more reading it looks like I may need a square bore to spread bore adapter, fuel line adapter, and throttle bracket, plus I'll need to splice in power for the electric choke......

Might not be worth the extra steps and extra cash now that I'm hashing it out. I may be just as well to go back with what I have and bolt in on, eh.

 

[dozerII]

Well, after some more reading it looks like I may need a square bore to spread bore adapter, fuel line adapter, and throttle bracket, plus I'll need to splice in power for the electric choke......

Might not be worth the extra steps and extra cash now that I'm hashing it out. I may be just as well to go back with what I have and bolt in on, eh.

Hey Jason if your going to replace the carb DON'T I repeat DON'T go with another qaudrajet, it is almost impossible to get a good one, both time I have tried I might as well have thrown the $500 out the window it wouldn't have felt so bad. In both instances once on the SS201 and again on the rat rod I ended up going with an Edelbrock and have never looked back.

 

[jasoutside]

Hey Jason if your going to replace the carb DON'T I repeat DON'T go with another qaudrajet, it is almost impossible to get a good one, both time I have tried I might as well have thrown the $500 out the window it wouldn't have felt so bad. In both instances once on the SS201 and again on the rat rod I ended up going with an Edelbrock and have never looked back.

Dood, I just pulled the trigger on one 30 seconds ago.:livid:

I went with National and supposedly they have a lifetime warranty, so, I'm thinking I should have backup if it's got problems.

 

[Patfromny]

I like Q-jets. The Edelbrock (carter) is alien to me so I can't comment on them. I have never had one so I don't know anything about them. I would go Q- jet or Holley. I think Holley makes a spread bore in a 600 but if you have already pulled the trigger on a Rochester then let it be. I think the Rochesters are better or smoother off idle than most so it should be the cats meow. Good luck with the Batts and new carb. Fingers permanently crossed for ya.

 

[dozerII]

Dood, I just pulled the trigger on one 30 seconds ago.:livid:

I went with National and supposedly they have a lifetime warranty, so, I'm thinking I should have backup if it's got problems.

I got my first one from National, it leaked through the welch plugs in the bottom and was jetted now where right for a 4.3, called them and they pretty much told me to pond sand. Back in the day before ethanol blended fuels I swore by Quadrajets, I will never waste another dime on one.

 

[jasoutside]

I got my first one from National, it leaked through the welch plugs in the bottom and was jetted now where right for a 4.3, called them and they pretty much told me to pond sand. Back in the day before ethanol blended fuels I swore by Quadrajets, I will never waste another dime on one.

shoot

 

[dozerII]

shoot

Hope you have better luck than me!!

 

[jasoutside]

Well, good news...

I pulled all the batt and accessory and charging wires in order to move the batts to the stern. Got one of the starting batts sitting where it's supposed to be and temporarily wired. Two FULL strokes of the throttle and that V8 fired up perfectly, very nice.

Now I know it's only been sitting for a day since my last start and I know I still have a carb dribble issue, but, putting those batts back next to the engine and eliminating that very looooong run definitely helped the situation. She starts up with way more authority now.

Lesson learned. As much as I wish to try and balance out the load in boats, batts go next to the engine and I find other ways to shift weight around:thumb:

 

[Patfromny]

Carbs have no pressure beyond the float. The vacuum demand from the engine pulls fuel through the venturies. The fuel pressure you see is from the fuel pump on non fuel injected engines and the float bowl shuts that off when the bowl is full. There is no reason for a carb to not perform the same in a matter of days. In fact, I would say that a carb should perform the same a month or two after the last fire. The bowl should still be pretty full. The bowl is just a storage chamber so the fuel should just be waiting there like water in a toilet bowl. Same principle. The full throttle pulls before start are to charge the system before start. A fuel injected system has pressure and most often, an electric pump and regulator and it depends on the pressure to operate. The injectors just open and close at a rate consistent with pedal or throttle position and the pressurized system supplies the fuel through the injectors. The injectors will also squirt a certain amount into the engine to start. Because the carb only works as an on demand unit, the accelerator pump takes up the slack by injecting fuel into the system before the engine is running. This is accumplished by giving the throttle a few full shots forward or stepping on the peddle twice before starting. It also adds extra fuel when punching the throttle to help the engine stay running until the venturi's can catch up. It is a total vacuum driven system or air driven. Not pressure driven. The pressure is there only to fill the bowl. Just like a toilet bowl actually. Leaking Welch plugs are something I have never experienced but I think every carb has them. Even my chainsaw carb. I've never had one leak. They are a super easy fix if they do. Drill out, pound in.

I think your problem is that you left fuel in the carb when you stored it and the ethanol ate the accelerator pump. I would recommend that you empty the bowl each year when winterizing. Actually, whenever you store the boat for more then a month. I would also recommend a fuel stabilizer. Better safe than sorry.

 

[Watermann]

I bet your new carb has the same starting sequence that I was nice enough to tell you about :lol:

Use only Non E premium fuel!

 

[jasoutside]

All right, after lord knows how many "sea trials" I have completed my final trial this morning. The V8 started right up and ran awesome!


One very happy and relieved middle aged chubby guy, one kid named Ryan, 60 gallons of fuel, worn out carb (new one is on the way), 4200 RPM, 50.5 mph, perfect morning!

:becky:

 

[Teamster]

Awesome!!!!

What is the max RPM on the motor???

You might be able to play around with some props and get even more out of it,.....

 

[jasoutside]

Awesome!!!!

What is the max RPM on the motor???

You might be able to play around with some props and get even more out of it,.....

4200 to 4600 is max WOT on this engine. Its fun now and then to go fast but I really have no need to go any faster.

 

[Watermann]

Oh yeah fitty that's great Jason! It drinks way too much fuel to have those 4bbls opened up but knowing you can scoot in an old boat is freaking awesome!