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Someone good with carbs

3K views 25 replies 12 participants last post by  bocajemma 
#1 ·
I'm looking for something that might be able to help out with a carb issue. I had it rebuild and put it on and can't get it set right. It's a Volvo pinta 454 with a holly carb. I have a hesitation when trolling. I go from 1.4 an up to 3.5 and top speed isn't there. Boat located in conneaut. Any info would be appreciated.
 
#4 ·
Hey guys I have a 96 sport and I just had the carb rebuilt and can't get it adjusted where I need it. I can go from 1.4 to a dead spot to 4 mph. It's a Volvo pinta 454 with holly carb. I dunno of anyone around the conneaut/Ashtabula way that has a vacuum gauge that can possibly help. Any into will be greatly appreated thank you
 
#5 ·
I assume you have an electric choke. That's my first guess. Make sure the choke is coming off correctly. That could cause both issues you are stating. I had carb issues two years ago. Was a nightmare. Carb was rebuilt 2 times by a Holley "guru". Couldn't figure it out. Just dropped a new Holley on and said goodbye to the old carb full of gremlins.
 
#9 ·
I bet it's ethanol related issue Franky. It's probably gota bad rubber on one of the needles.

Look online there's places you order and get a rebuild that's been bench floated and you send them urs as a core...
 
#11 ·
You are running rich at idle. Most likely just need to lean out your idle set screws. I had similar issue on my Holley. The repair shop had my idle set screws at 2-1/2 turns out. Would load up with carbon when trolling. I bought vacuum gauge and adjusted the set screws and ended up at 3/4 turn out. They had set it way too rich. No more carbon loading and no more gas sheen on the water when idling at the dock.
 
#14 ·
Are you talking idle set screws? Baseline is 1-1/2 turns out for Holley 4 barrel. One set screw on each side. You adjust from there to obtain the highest vacuum reading. Adjust one side at a time in small increments. If you get a backfire you are too lean. Adjusting out is richen adjusting in is leaning. At the end both idle set screws should be set the same. If it's one turn out both set screws should be one turn out. Go to the highest vacuum and then back it off (turn screws out) an 1/8 to a 1/4 turn to have just slightly richer than highest vacuum lean idle.
 
#20 ·
When was the last time you checked the wires and plugs Cap rotor and points if equipped?
I'm assuming you have a vac secondary carb so you should only have two idle adjustment screws, if you can turn them with no change you either have the idle rpm set to high or the throttle plates are open to much. (which is a possibility if the rebulider adjusted them). Set it too high and you miss the idle circuit completely. If you had a backfire you may of blown the power valve out, but the new kits have a check ball you install under the base plate to prevent that from happening now.

If it was rebuilt correctly and you are having troubles with top end and idle I'd check the distributor and timing first. If the weights and springs are shot you'll have problems on both ends with the timing curve.

Also get two new spark plugs. (idle Adjustment)
Install one on the engine already warmed up to temp. start it and idle it for a min or two, kill the motor pull the plug and check it. Now it should smell like gas and look a little rich but not be soaked in gas.
Then
Take the other new plug put it in (jet adjustment)
Start her up and immediately take a hole shot up to WOT for about 1/8 mile then Immediately Shut it off, Your trying not to let it hit the idle circuit. Now pull and check that plug. you should have a nice clean plug if not your jets are off. or have the wrong powervalve.

Without a wideband A/F gauge you'll have to read plugs and vac gauges along with a timing light to get a general idea of where you should be.
Remember always set timing FIRST then adjust for best vac then adjust for idle rpm.
 
#22 ·
All of the ignition parts have been replaced this year , the frustrating part is it runs great from 1000 rpm to 3800 but I still believe it's the carb . It's never carbon fouled plugs like this in the past . But the only variable is the rebuilt carb this spring . I need to have someone take a look at while it's on the boat , they might be able to tune it or find something I'm missing.
 
#23 ·
So everything's new this season then. Points or hei? Have a vac advance canister on it? All plugs look the same? And yes you need to tune it on the boat or you're just guessing completely! Most holleys will run right out of the box on base settings. Holley has an awesome website for trouble shooting and tuning. Get a timing light better yet a dial back light and a vac gauge and check your inital and total. Trollers aim for low initial timing and not stalling. Race boats go for max timing without pinging.
 
#25 ·
  • Just a couple of things you could check,, is the thermostat operating? if it isn't getting your engine up to proper temp it won't idle, same as an automobile,, also what type of spartk plugs are you using? If they are the gapless type,, that type of plug is made for boats that are operated at a high speed i.e. ski boats and the like,, plugs will foul if trolling and such,, use the proper heat range plug with the electrode, these are just a couple things that I have learned through experience and information from a very qualified marine tech,,
 
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