looking for replacement carb, any ideas?

[OMARiverRat]

Hello fellow boaters. I'm looking for some help, as I am new to the boating world. I have a 1990 Mercruiser 5.0L 305 w/ Alpha One drive. After posting a thread a month or so back, I've concluded I need my carb rebuilt (hard starting, occasional backfire, hesitation under load). The carburetor on the boat now is a Mercarb 3310-807312A1 2bbl. I've decided to let a professional handle the rebuild, but the local marine center & repair shops want at least $350.00 for a rebuild. Seems awful steep to me. After looking around a bit on the web, I've found a few reman carbs for $250-$350.00 each, manufactured by Rochester & Sierra. One particular website I found (www.theshadconnection.com) has a direct replacement Rochester, Part #187611 for only $245.76 + $15 shipping. Can anybody tell me if I'm heading in the right direction with this? I want to have a reliable boat for the upcoming season, but at the same time I hate to spend $500.00 on a brand new MerCarb. Any thoughts/suggestions would be greatly appreciated. Also, does anyone know any simple tricks for carb dial-in, or perhaps a website which describes proper carb adjustment? This is my first boat, and I've always had EFI Vehicles. Thanks for your time, & happy boating!

 

[Walt T]

Re: looking for replacement carb, any ideas?

If it needs to be rebuilt, there is no amount of tweaking that will make it work. Try a local automotive carb rebuilder, that may be less expensive. They'll understand it is a marine carb.<br />Your symptoms do sound like a carb problem but I would be trying some adjustments to verify it needs an overhaul. Most boats that were sent to me for carb overhauls only needed proper adjustments. <br />You should be able to buy a reman carb for 200-400 dollars. I would not buy a new one.

 

[Trent]

Re: looking for replacement carb, any ideas?

Look here also...<br /><br /> web page

 

[dmartin1215]

Re: looking for replacement carb, any ideas?

I have an Invader 198..4.3 LX. It came stock with a 4bl carb. I ordered a Edlebrock marine carb from Summit Racing 2 years, ago for about $250, and it has worked awesome. No more lean pop, and it starts easily every time. No way was I going to pay $500 for an identical replacement! I don't know if they have one in a 2barrel, but it would hurt to try.

 

[OMARiverRat]

Re: looking for replacement carb, any ideas?

Thank you everybody for the replies so far. Has anyone ever heard of www.i-5automotive.com ? They have a direct replacement MerCarb, Remanufactured, bench tested & adjusted, 6 mo. warranty for $215.00 + $8.00 Shipping. I spoke with someone there and he expalained to me the installation/dial-in is extremely simple. According to him the only thing that may need adjustment is the "RPM" or idle screw (small screw w/ a spring around it)

 

[fireship1]

Re: looking for replacement carb, any ideas?

Hello, Mixture screw will also need to be adjusted after installing the new carb. It's a simple job. You'll need a vacuum gage and a screwdriver. You need to tap the vacuum gage into the intake manifold and fiddle with the mixture screw until you obtain the highest and stediest vacuum reading. Then reset your idle speed while in gear and you will be all set. Hope this helps!

 

[OMARiverRat]

Re: looking for replacement carb, any ideas?

Fire, thank you for the info. This may sound really stupid, but which one is the mixture screw?? <br /><br />Thanks again,

 

[Walt T]

Re: looking for replacement carb, any ideas?

This is kinda what I was afraid of. Yes it is a simple procedure. But look fellas, this guy doesnt even know a mixture screw. How will you tell him to adjust the secondary restrictor? How are you going to tell him to adjust the idle using the idle drop method? How are you going to describe the proper choke adjustment procedure? How do you tell him to set the final curb idle speed? Truth is most of the so called mechanics out there (And a lot of them here) dont understand carburetors. No offense River Rat, I'm sure you're an intelligent person. After all you have sense enough to know when you need help, not like a lot of folks I've seen. Trying to properly adjust and diagnose a carburetor is not a job for a 'mechanically inclined guy'. It's a job for a pro, and herein lies the rub. As I said there are a lot of mechanics that don't understand carburetors. How do you know the mechanic at your dealership knows what he is doing? Maybe he just replaces carbs and hopes the problem is fixed. Don't laugh, this is how a lot of 'problems' are fixed. I read a post here where a marine mechanic told a customer to take his boat to an automotive guy to get his carburetor worked on. At least the marine guy was honest. <br />To find a mechanic that knows carburetors ask him this question:<br />What are the four circuits in a carburetor? He/she should be able to answer without hesitation.<br />I'm sure everyone here with access to google can answer that one.<br />Check out a basics article about carburetors I wrote here:<br /> Carburetor Basics

 

[fireship1]

Re: looking for replacement carb, any ideas?

Hello, Mixture screw will be the screw with the small head and a spring on the shaft. It will be tapped into the side of the carb near the base. The idle speed screw will also have a spring on the shaft but has a larger and wider head. Idle speed screw will be where the carb linkage connects. Use a service manual when completing the carb tune up procedure. Follow all of the steps in the manual so you adjust it properly. This is an easy carb to tune next to some of the other carbs out there. If you really don't feel comfortable doing this yourself take Walt's advice and have a pro do it for you. If you feel up to it go ahead and give it a go, you'll figure it out with patience and a manual. Let us know how it goes. Good luck!

 

[OMARiverRat]

Re: looking for replacement carb, any ideas?

Sounds good, I will give it a shot. I appreciate everybody's patience with the "newby" boater. Thank you all!

 

[Ralph 123]

Re: looking for replacement carb, any ideas?

I also use Edlebrock Marine Performer series on my 350s and they are awesome. The nice thing about buying a brand new card like this is you get a owners manual with them that give you step by step indtructions on installation and adjustment. If you shop around you can get a brand new Edlebrock for little more than a rbuilt merc.

 

[Ralph 123]

Re: looking for replacement carb, any ideas?

I found the link:<br /><br /> http://www.edelbrock.com/automotive/marine.html

 

[Bondo]

Re: looking for replacement carb, any ideas?

Yep, That Edelbrock carb is a Beauty........<br />It's Also an Exact Carbon Copy of the Merc/Weber carb used by Mercruiser......<br />The Tuning Kit for the Carter/Edelbrock IS the Kit to Tune the Merc/Weber carb...... Much Cheaper,+ Easier to get than Merc. Parts........(BTW, the carb kits,+ gaskets are Also Exactly the Same)<br />That 600cfm is the Ideal Carb for the 4.3ls,+ the 5.0ls,+ the 5.7ls......<br />The 750cfm is the one used by Merc. on the 7.4ls.....<br /><br />You Can't go wrong with these carbs....<br />Super Easy to work on,+ Tune................

 

[OMARiverRat]

Re: looking for replacement carb, any ideas?

Would I see a huge difference in fuel economy upgrading to a 4bbl from a 2bbl? Would I see any difference in performance? Obviously the ideal thing to do is swap out the intake manifold with a 4bbl intake, but would there be a significant difference in power if I was to install a 4bbl to 2bbl adapter plate?<br /><br />Once again, thank you all for your help.

 

[LubeDude]

Re: looking for replacement carb, any ideas?

Dont do the adapterplate thing, you would see only part of the performance that the carb is capable of, and yes, the edelbrock carb is as good as people say it is, You wont be disapointed if you do the change over! Im not convinced that you are going to get a fuel usage imrovement thought. It is posable though as you will not have to have the throtle down as far to maintain cruising speed! If you are at WOT you will use a bit more fuel!

 

[Walt T]

Re: looking for replacement carb, any ideas?

No huge differences, even with the manifold

 

[Northern Eclipse]

Re: looking for replacement carb, any ideas?

I'm Glad to read that a few folks like their Edelbrock Carbs I just bought a Brand new 600cfm performer I can a hardly wait to bolt it on.<br /> OMARiverRat you should be to able to get it rebuilt for about 200 bucks if you take it off yourself, personally If I had to spend that much on a Mercarb I would chuck it out and replace it with a Rochester or another known brand, The Mercarbs are knock offs and have been known to be problematic with flooding and rich running. I'm getting rid of mine and replacing it with a Edelbrock, I'm sick of cleaning the black crud off the back of my boat, My Mercarb was a problem from brand new its been rebuilt twice at Mercurys expense and once at mine since 1991.

 

[Ron Everson]

Re: looking for replacement carb, any ideas?

I'm the guy that the marine mechanic sent to the automotive mechanic down the road for carburetor work. Based on the recommendations of the auto mechanic, I ordered an Edelbrock marine carburetor out of his JAG catalog and he installed it. The original Rochester was 4 barrel and so was the replacement Edelbrock. He liked it because it came with a kit containing different jets and parts with which to fine-tune the carb. The Edelbrock has performed well for 4 years or so. I did notice that the engine choked while accelerating quickly a couple of times last fall, so I probably need to take in to him for a checkup. I normally set the timing myself, but I will seek the help of someone who knows when it comes to any changes to the carburetor other than choke and idle speed. By the way, the auto mechanic bought a small water tank to dip the outdrive into while running the engine in his shop.<br /> Ron

 

[OMARiverRat]

Re: looking for replacement carb, any ideas?

Thank you all for the help you've so graciously donated. For the time being I've elected to install a reman 2bbl Carb back on the boat. The carb showed up Friday, everything looks identical to the existing carb. I went to install it yesterday, and you guessed it.... Tried to loosen the fuel line and the elbow just before the carb fitting kinked and broke. Now this is somewhat off of the original topic I had for everybody. But I'm wondering if its possible to install a flexible rubber fuel line over the existing rigid fuel line, and install a barbed fitting on the front of the carb, and connect it with hose clamps? This would eliminate the purchase of an entire new fuel line from the fuel pump. I am not certain if this is legal, or safe at all. Please let me know your thoughts. <br /><br />Thank you much.

 

[charleswmoore]

Re: looking for replacement carb, any ideas?

Up untill a recent posting I would have said no to a flexable hose. Since the person that corrected most of us in regards to stated the ruling and supported it with CG documentation it seems both are exceptable provided it is of approved material. I have always disliked the steel lines with copper being too fragile to vibration. Search recent postings it is interesting reading regarding this ruling.<br />Maybe someone else can give you an exact posting date.