View Full Version : I want a more reliable carb
08-24-2010, 01:39 AM
I have a '85 Stars & Stripes. 351, Holly 650. The carb has been rebuilt 3 years ago but needs too much work to keep it adjusted well. I want to replace it with something more reliable. I also plan to switch to electronic ignition and electric fuel pump.
Any suggestions on a good replacement?
08-24-2010, 08:04 AM
Hey, I rebuilt mine and it ran fairly well for about a year. It always had cold start and idle issues. I purchased and installed one of these carbs.
Starts right up and idles when cold.
08-24-2010, 11:24 AM
Buy a new one and maybe look at how you use or store you boat. All that rebuilding could be you. Carburetors do not like alcohol fuel or to be left sitting with fuel in them. One problem we have with our boats here is lack of use or seasonal use. I am a firm believer in running engines or draining fuel if they sit more then three months. I also use stabilizer if I leave fuel in them even when I still use them occasionally. Electric fuel pumps can be a bad idea. Not going to give the name of the electric fuel pump but it is a popular fairly expensive name brand fuel pump and they out last the cheaper ones by a year. I have electrics on two boats and they go out approximately every two to four years. There has been a lot of discussion in my group about why we have so many problems keeping fuel pumps on these high hp engines. The usual consensus is that if these engine blocks had mechanical fuel pump openings---we would run them and carry electrics for back up to quickly bypass a mechanical if it started leaking in the field. I have a mechanical on one other boat----it has never gone out. Mechanical were all we had at one time and electrics were used only when we built engines that a mechanical could not keep up with or we were trying to cut down on parasitic horse power loss. The few mechanical fuel pumps that I have had go out always surprise me just to the longevity they achieve. It is your boat and you can do what you like but I thought I would give you an opinion based on being around boats all my life and the problems we have with carbs on our boats and fuel pumps.
08-24-2010, 11:41 AM
Stick to a mechanical fuel pump. I only had to replace mine once in 28 years.
I bet you will never hear anybody say that with a electric fuel pump.
08-25-2010, 12:26 AM
I'm on 24 years and going strong, where is that pump located? Haven't had the need to replace it. From Ski King's post I guess I have about 4 years before I need to locate it.
08-25-2010, 01:38 AM
Thanks for all the info. I live in the Colorado mountains so it is a short season. The boat sat for 5 years before I bought it so it took a lot to clean the entire fuel system. My carb was rebuilt and jetted by a company that rebuilds Shelby's from scratch and they dyno'd it on one of their trucks before we reinstalled it.
The Holley 4160 was recommened. Do you like this carb?
From your post and all the others, an electric fuel pump was a bad plan.
08-25-2010, 01:42 AM
The pump is attached to the engine. It is 25 years old and hasn't been a problem before. A mech pump is clearly the way to go.
08-25-2010, 10:38 AM
I really enjoy the way the boat runs now after installing the new carb. Pump the gas twice turn the key fires right up and idles smoothly when cold. With the old carb you had to feather the gas when doing cold starts or it would die. It has been the single best upgrade I've done to the boat.
08-26-2010, 10:05 AM
Both a local inboard only race boat shop and a nationally regarded race boat engine builder (see link below) steered me to the Edelbrock marine carbs (600 and 750CFM only) because of their increased reliability. I'm going with a 750 in the off season on my 454 due to my 20 year old Holly that is worn out. It's dripping from the venturi clusters and needs a new main body.
08-26-2010, 11:30 AM
Interesting, Matt - I think you are the first person i've seen suggest using an Edelbrock carb. My long-time auto mechanic buddy told me "when you're tired of messing around with your carb every 3 months, put it in the garbage and go buy an edelbrock." Thus guy rebuilds classic (56,57,58) Chevy's for a living. While I respect his automotive opinion, I wasn't about to run out and replace my holley in this marine application. I'd be really interested to hear how that works out for you
08-27-2010, 11:21 PM
Replaced original Holley on my '84 S&S (after having it rebuilt twice)with the Edelbrock marine carb-easier to start,ran fine. According to mechanic/friend Holleys develop air leaks around throttle shafts. The Edelbrock did run rich at idle,never got around to fine tuning before selling boat.
08-28-2010, 08:15 AM
The throttle shafts on all carbs will leak air eventually. That is a friction area that eventually wears. A good rebuilder would catch that.
08-31-2010, 11:54 AM
I have an 84 S&S and having carb issues as well, Rebuilt 2 years ago, but don't trust the dealer who did it. ( they recently lost their MC dealership) The day I got my boat back we had no secondary's and found they had reversed a gasket and blocked a hole.
Anyone know which Holly came stock on the 84? 4150? 4160? something else? Where is the model tag?
Recently it started hesitating or dying when punched, then just died and could not restart. Was dripping when engine was stopped.
Removed secondary and primary bowls, spray cleaner and replaced. Now starts, no drip, but dies around 2500RPM.
Can I spray Carb cleaner to check for vacume leaks around the throttle shafts and gaskets?
Not sure if the floats are set correct, but see no adjustments externally.
Want to buy a new 4160, but can't afford it.
08-31-2010, 01:55 PM
84 probably had a 4010. Many many threads here discuss people with 4010 problems (search for 4010 in the search window) - these carbs were temperamental and susceptible to heat problems.
If you have a standard 351W, the carb you want is a 600 CFM vacuum activated secondary marine carb with electric choke, with either single or dual fuel intakes (most seem to have single, some HO engines came with the duallies) like this one:
Some educated reading will show you that rebuilt/remanufactured carbs are hit-and-miss at best. There is a huge thread about some recent major problems with carbs from National Carbeurator, FYI (they sell "rebuilt" carbs for about $250 on ebay... buyer beware, you may get what you paid for)
Answering your other questions: The model tag is stamped on the air horn, under the fire arrester. It may be a proprietary number ,however, based on whomever marinized the engine.
The 4150 and 4160 both come in a dozen variations, including single or dual fuel intakes, marine and non-marine applications, and of course, different CFM ratings, as well as choke options. When you go into the marine-specific ones (which you absolutely want, it would be a fire hazard not to have a marine carb) - most have electric choke, so the variables are down to CFM and fuel intakes.
The only difference, other than the above, between the 4150 and 4160 is the secondary metering block. On the 4150, you have dual adjustable metering blocks, jets, and power valves. On the 4160, the secondary metering block is replaced with a fixed metering plate - no power valve, no idle jets, no ability to adjust the main jets. Honestly, unless you run in a high altitude environment, there is no real reason you need a 4150. Also, if you buy a 4160, you can buy a secondary metering block from holly for $50 if you decide you need it later on (essentially converting your 4160 into a 4150)
If you don't have a screw and nut at the top of your fuel bowl to adjust the float levels, then it is an internal adjustment only float. Likewise, the older 4010 didn't have any inspection screws, so you basically had to set the float level, prime the carb, test for overflow, and then drain it all out, take it apart, re-adjust, and re-assemble till you got it right. That's a major pain. Newer carbs have a plug/screw that you can unscrew and check the fuel level, and the floats are adjusted with a screw on the top of the carb. Pictures attached.
You absolutely can check for vacuum leaks around the base gasket, throttle arm, etc. I would also hook a vacuum gauge up to an open vacuum port (or "T" the breather hose if you don't have a port open). Your idle vacuum should be at least 8 inches... most people around here seem to say 12-15, but i think mileage varies greatly. Your power valve should be a 2.5", meaning anything over about 6" of mercury is going to guarantee that your power valve is closed at idle (which is what you want)
May I also recommend that rebuilding these carbs is a trivial process? Takes a few hours and some patience, but for about $30 you can do it right. There are many guides on the web, and some helpful members with printed documentation and powerpoint/PDF guides that can help you step by step (I can forward via email, PM me if you need)
1) 4160 dual fuel inlet carb (on top my 454)
2) float bowl inspection screw
3) float adjustment screw (note there are two different models of this, depending on if you have side-hung or center-hung floats... these are center hung)
08-31-2010, 02:56 PM
Great writeup and information thank you!
08-31-2010, 03:49 PM
Fantastic info. Just what I needed. Thanks. I do hear that you can only rebuild so many times, and since this is the original 26 Yr old carb, ( I assume ) I wonder if I go through the effort , will I still have problems, especially since you suggest the 4010 has problems to begin with. I will PM you regarding the docs, but I will also take some pictures tomorrow and post them, as well as check the model tag to confirm it is a 4010 if possible.
Sounds like I may need to save up for the 4160, but would love to get mine thru the rest of the fall season.