Carb problem?

[galaxy]

77' 165 Mercruiser. Had been running pretty good on the lake for about three days. I did notice some surging periodicly. I've replaced plugs, points, cap, plugwires, coil, fuel filter, set timing, re-built carb, adjusted idle mixture. Last day at lake decided to pull my son skiing. Hit the throttle and it died. Idles and throttles fine in neutral. Put it in forward and throttle up...it dies. It will idle (750 rpm's) in forward gear all day long, but throttle up and... well, you know, dies. Pulled a couple of plugs and they were black and sooty. I'm suspecting carb problem. Original 2 bbl Rochester. When I re-built it, I did notice it had a lot of pitting in the metal inside the bowl area. I did clean it out very good. I know brass float level is correct. If it is the carb, I'm thinking about buying a new one. Any idea's. Thanks

 

[flashback]

Re: Carb problem?

buy or rebuild the carb

 

[galaxy]

Re: Carb problem?

I've already rebuilt it. I've read the idle mixture screws should be out roughly 1 and 1/2 turns. I've been only able to get a good idle with about 1/4 of a turn out. Turns ...being counterclockwise from the seated position.

 

[Bondo]

Re: Carb problem?

Sounds like it's time for a New carb.....

 

[galaxy]

Re: Carb problem?

If my carb was the problem, why would it run fine in neutral? My father-in-law say's it sounds more like a timing problem. My problem is getting the prop under a load "while setting in my driveway".<br />Any ideas out there besides muff's?

 

[medic]

Re: Carb problem?

By no means an expert here, but it still sounds to me like the carb. Mine was doing that and some other stuff. Rebuilding the carb now. Please post what the problem was when you get it fixed. I would check the float again and the needle jet.

 

[Bondo]

Re: Carb problem?

It's a carb Problem,<br /> Because;<br /> "Pulled a couple of plugs and they were black and sooty." <br />And, "notice some surging periodicly" <br />And, ", I did notice it had a lot of pitting in the metal inside the bowl area." <br />And, "I've been only able to get a good idle with about 1/4 of a turn out." <br />And, What it'll do in the driveway, in Neutral, Has Nothing at all to do with what your doing.....<br />Because, "My problem is getting the prop under a load " <br /><br />Without a LOAD, there is No Problem.....

 

[flashback]

Re: Carb problem?

sounds as if it is getting too much gas and flooding out. replace the carb.....

 

[galaxy]

Re: Carb problem?

I've been reading up on carburetors and understand that there is a difference in the way they are manufactured as far as auto verses marine type. I think I should go with a marine carb. Any good prices out there on the net?

 

[magster65]

Re: Carb problem?

Without a doubt use a marine carb... not sure about prices but before you buy a new one make sure your accelerator pump is working and double check that float level.

 

[galaxy]

Re: Carb problem?

Will do, Thanks.

 

[joeG]

Re: Carb problem?

I agree...check the accelerator pump first before you buy a new carb. Have someone hold the choke open and have them look down into the carb. Have another person at the throttle and have them push the throttle down as if you were pulling a skiier. Make sure that the person looking into the carb sees two good streams of gas dumping into the carb. If not, your accelerator pump is bad. (by the way...do this stuff with your motor off!)<br /><br />I know that a 2bbl Holley will run you about $300-$350 brand new, don't know anything about a Rodchester.<br /><br />-Joe-

 

[flashback]

Re: Carb problem?

This boat is a 1977 model, save your self a lot of hassle and get a new carb, the darn thing is 25 years old and not worth the trouble to rebuild unless you are changing jets,needles,floats and every thing else and vat it out to boot.......

 

[galaxy]

Re: Carb problem?

I agree with ya Flashback. This motor is worth a new carb. When changing valve cover gaskets and pushrod cover gaskets This thing looked so clean inside I couldn't believe it was a 77'. Not sure I want to go back to a Rochester. I've always been partial to Holley's. Cost more maybe but worth it in the long run.

 

[flashback]

Re: Carb problem?

I have heard that holly's are prone to leak around the accelerator pump. I can personally recommend the AFB carb from edelbrock, I got one 2 years ago and it works super. cost about 350.00

 

[galaxy]

Re: Carb problem?

Thanks for the tip, Flashback. I'll look into getting the Edelbrock.

 

[galaxy]

Re: Carb problem?

Well, I bought a remanufactured Rochester carb from BFIC via the internet and man what a difference it made! That 165 Mercruiser runs and idles like a new engine now. $165.00 bucks is all it cost me. WOT was 3200 rpm @ 30 mph. I was hoping it would do a little better than that. I'm thinking it could be the prop. However, the prop I have on there now is a 19 pitch. Shouldn't I get a little more top end speed with that pitch? I'm still not going to complain too much though, concidering the way it was running before the carb change.

 

[magster65]

Re: Carb problem?

Good news <br />You can afford lose a couple inches of pitch to get your rpm's up to what they're suppose to be. Make sure the hull is clean and full fuel/water when you test for WOT rpm.