Engine dying on throttle up.
Printed From: CorrectCraftFan.com
Category: Repairs and Maintenance
Forum Name: Boat Maintenance
Forum Discription: Discuss maintenance of your Correct Craft
URL: http://www.CorrectCraftFan.com/forum/forum_posts.asp?TID=13641
Printed Date: November-17-2024 at 4:37pm
Topic: Engine dying on throttle up.
Posted By: vondy
Subject: Engine dying on throttle up.
Date Posted: May-11-2009 at 4:20pm
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I started discussing this in another post but want give it its own one.
When throttling up from idle with the choke plate fully open the engine dies. Unless I "gun it". Then it sees to run, mostly at least. Could this be a fuel filter problem? I would assume the air/fuel mixture screws are not a concern as they are for the idle. Not sure what else can be adjusted. The carb was rebuilt last year and fogged before winterizing. It stays running if I close up the choke plate manually. Fuel pump is also new last year. Fuel was stabilized as well. This is an original Autolite carb on a 302 H/M. Thanks. ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Replies:
Posted By: 79nautique
Date Posted: May-11-2009 at 5:29pm
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Accel pump needs checked/replaced or the choke is coming off too soon ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: vondy
Date Posted: May-11-2009 at 6:00pm
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I'll check the Accel pump 79, it was replaced last year so I would think it's still good. Maybe something got in it.
I replaced the choke with an electric one and can't really change how fast it opens, not that I am aware of at least. Either way, if I have let it idle for 5 minutes or so, shouldn't it be well beyond the choke point? At least on an 80 degree day? thanks! ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: Tim D
Date Posted: May-11-2009 at 8:11pm
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Power valve too. ------------- Tim D |
Posted By: 79nautique
Date Posted: May-12-2009 at 11:05am
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accel pump needs adjusting, not neccessarily replaced unless bad. the choke does has some adjustment to it that's why you can rotate it but after 5 min no it's done.
So a carb issue most likely. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: vondy
Date Posted: May-12-2009 at 11:42am
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One thing I noticed, when I look down the carb and press the accel pump, I see fuel inject into the port side barrel only.
The manual I'm looking at says "...fuel passes through the accelerating pump discharge screw and is sprayed on each booster venturi through discharge ports in the nozzle bar assembly." Should I see fuel in each? ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: eric lavine
Date Posted: May-12-2009 at 11:48am
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gotta feed both banks, yes ------------- "the things you own will start to own you" |
Posted By: 79nautique
Date Posted: May-12-2009 at 2:38pm
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both sides and for the complete stroke.
meaning as soon as the throttle is opened up gas should start squirting into both sides almost instantly and continue untill fully opened. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: newoldboat
Date Posted: May-12-2009 at 11:54pm
| I agree with the other guys, if you hit the throttle and only one venturi discharges then you will have to check the accel pump. The diaphragm may have been damaged when you had it rebuilt. If you can get the engine to accelerate does it run correctly up to high idle? If you can get the motor to run past the stumble when accelerating, and it will go to high idle then it is deffinetly the accel pump. The whole rebuild kit is only about $50. |
Posted By: vondy
Date Posted: May-13-2009 at 11:01am
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It's fixed. I think.... at least now both sides are working. Cleaned out the nozzle and now the fuel is flowing. I haven't started her yet but probably will this evening. Thanks to you guys, I'm sure I saved myself a lot of trouble. Took all of two seconds to fix. And I learned a bit more about carbs.
Thanks! ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: 79nautique
Date Posted: May-13-2009 at 5:57pm
if your carb has a high idle cam then you have the wrong carb because it's automotive, marine applications do not have a fast idle cam or high idle setting on the carb. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
newoldboat wrote:Posted By: TRBenj
Date Posted: May-13-2009 at 6:20pm
Wrong meaning unsafe? Maybe. Wrong meaning non-original? Maybe not... were the late 60's Autolites available in a marine flavor? ------------- |
Posted By: vondy
Date Posted: May-14-2009 at 1:27am
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Well I thought I had it fixed. Ran her today and pretty much the same result. Slowly accelerating kills her. And I had her plenty warmed up. Thermostat open.
Looking down the carb, as soon as I touch the throttle, the jets inject fuel. It kind of hard to tell but it seems like it's not a constant stream. Unless I accel faster. Also, my idle seems a little rough. If rough is the word. It's going along nicely then the RPMs drop a bit the bounce back up. It will do this off idle as well. My Autolite has a fast idle cam, slow idle cam, all that stuff I don't know if it does anything. ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: Gary S
Date Posted: May-14-2009 at 1:30am
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He's got the original one on there and no it's not marine but neither was the fuel pump or distributor. Save your money David,the best thing to do someday is to replace it with a Holley,it makes a difference. My offer still stands if you want my old one. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: 74SkiNautique
Date Posted: May-14-2009 at 9:54am
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The accel pump deffinatly needs checking. Open the choke plate and manually pump it once or twice. You should see two STREAMS of fuel shooting into the center of the throat. My 74 did the same thing. The holes could be clogged, or maybe you have the wrong cam in or possibly its in backwards. Its a fuel problem because when you close the choke, it gets better meaning not enough fuel. ------------- 74SkiNautique |
Posted By: 74SkiNautique
Date Posted: May-14-2009 at 9:56am
The Holley 4160 is what mine has. The 4150 is the same but has two accelerator pumps right? ------------- 74SkiNautique |
Posted By: vondy
Date Posted: May-14-2009 at 11:34am
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I guess I'll pull apart the pump and check it out. There are two steams when I manually pump. Although they sometimes seem to be broken streams.
74 what cam are you referring to? Something to do with the accel pump or are you talking about the fast idle cam? Gary it's a great offer for sure. Not sure how much good it would do me. I cleaned mine pretty good last year and rebuilt. I'm hoping I'm just missing some small with this problem. The Holley is on the list right after the stringers. And I keep asking this question and I think 79 answered the last time but not sure I understood correctly. In this pic, should this tube be capped off? I swear I feel a vacuum on it. 
And on the choke. Should I remove this cap on the hot air intake now that I have an electric choke? Would that cool the choke coil making it open slower? Mine opens in like 30 seconds, seems fast. But I could be wrong.  ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: 74SkiNautique
Date Posted: May-14-2009 at 2:18pm
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I am not familiar with your carb, but on my holley, there is a rubber cam that rotates on the throttle body, which moves the lever on the accelerator pump. If it is the wrong shape, then it would add too much or too little fuel. Different cams are for differant jobs.
The streams will shoot slowly if you move the pump slowly. but if it is not a steady stream when pumped fast, somethings wrong. Mine was just dribbling down the side of the throat which cause dying at acceleration and no power. ------------- 74SkiNautique |
Posted By: 79nautique
Date Posted: May-14-2009 at 4:54pm
then your Holley would not be orginal equipement either as that is not typical of the 4160 carb's PCM sent out the door. ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=756&sort=&pagenum=1&yrstart=1979&yrend=1979 - 79 nautique |
Posted By: 74SkiNautique
Date Posted: May-15-2009 at 1:22am
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Yes mine is original, it says right on the primary and secondary float bowls, HOLLEY, and stamped on the side is mo. # 4160 I even bought the service manual for it, and it matches up perfectly. ------------- 74SkiNautique |
Posted By: vondy
Date Posted: May-15-2009 at 1:38am
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Pulled the carb, going to soak it. I just sprayed with carb cleaner last time. Should have soaked overnight. It looks like it could be cleaner. Hopefully she'll be working better afterwards. ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: Gary S
Date Posted: May-15-2009 at 1:40am
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David for sure cap that tube.With that open you have an air leak.You can see the original cap is still on there.Being an automotive carb it is there for other purposes that your not using.When I get a chance I'll look at mine and see if there is a cap still inplace on my choke ------------- http://www.correctcraftfan.com/diaries/details.asp?ID=1711&sort=&pagenum=1&yrstart=1966&yrend=1970" rel="nofollow - 69 Mustang HM SS 95 Nautique Super Sport |
Posted By: vondy
Date Posted: May-15-2009 at 3:05am
Gary, yours is capped in the pic.
Apparently the tube is a distributor vacuum tube for the auto side.  ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: vondy
Date Posted: May-19-2009 at 5:51pm
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Soaked the carb overnight and rebuilt. All is well now. ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |
Posted By: Guests
Date Posted: May-19-2009 at 6:27pm
| that sure does look like an automotive carb can you take a shot of the top so we can see if it has J-tubes? |
Posted By: TRBenj
Date Posted: May-19-2009 at 6:44pm
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Posted By: vondy
Date Posted: May-19-2009 at 6:44pm
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These definitely were auto carbs. No J tubes. ------------- http://correctcraftfan.com/diaries/details.asp?ID=4645&sort=&pagenum=1 - 69 Mustang HM |