Rochester 2GV tuning

turpehar

Cadet
Joined
Jul 25, 2007
Messages
26
I have a 1982 Celebrity 898, 188v. This has a Rochester 2GV setup. I've had the boat less than a month and it's my first one ever.

We took it out twice and it would not idle after having it in the water for a couple of hours. I've been wrenching on all sorts of vehichles for over thirty years so I applied general knowledge in diagnosing my issue.

My appraoch was to clean/empty the entire fuel system. Tank emptied, hard lines removed/cleaned, rebuild carb, replace fuel/water separator, replace plugs with OEM recommended.

Every thing went well, and after finnaly getting a prime off the fuel pump it ran fine with two exceptions. 1)there is a lag in throttle response, but if you advance slowly it comes up fine. 2)Fuel consumption seems high, but not knowing the characteristics of the gauge or the size of the tank it's hard to tell.

The real question is looking at the front of the carb, there are two screws in the base, I am presuming idle and mixture. I have not been able to find true information on this particuler carb that tells me how to tune.

In addition, I'm only getting 3800 rpm WOT. I think this is low but you need some background. When having trouble idling the second time out, during the course of trying to return to the trailer, we drifted and I got in too shallow and dinged the prop pretty good. I dressed it up a bit and went on. I understand that a bad prop can reduce your RPM's. What are you thoughts?

Any help is appreciated.

Thanks
 

95yj

Petty Officer 1st Class
Joined
Feb 21, 2007
Messages
279
Re: Rochester 2GV tuning

Actually, that's two idle mixture screws and is one way to tell whether you have a Rochester or MercCarb as the the Merc only has a single idle mixture screw.
 

turpehar

Cadet
Joined
Jul 25, 2007
Messages
26
Re: Rochester 2GV tuning

Actually, that's two idle mixture screws and is one way to tell whether you have a Rochester or MercCarb as the the Merc only has a single idle mixture screw.

So each idle mixture screw controls its perspective bore?
 

95yj

Petty Officer 1st Class
Joined
Feb 21, 2007
Messages
279
Re: Rochester 2GV tuning

That's my understanding, but I never had to work on one. The boats that I had with them ran good and I didn't have to muck around with the carbs.
 

Don S

Honorary Moderator Emeritus
Joined
Aug 31, 2004
Messages
62,321
Re: Rochester 2GV tuning

That's my understanding, but I never had to work on one. The boats that I had with them ran good and I didn't have to muck around with the carbs.


Why do you keep answering questions if you know nothing about it? Seems strange to me, and probably confuses the hell out of the people that try some of your suggestions.


turpehar
Sounds like you may be having problems with fuel delivery TO your engine.
Try this test when you are having the problem, hook the gauge up and go for a run and watch it.

http://forums.iboats.com/showthread.php?t=167561
 

MurphysLaw

Cadet
Joined
Jul 28, 2007
Messages
29
Re: Rochester 2GV tuning

Just to be sure, I would also check it to be sure that you have the correct carb on it. There should be a 8 iirc digit ID number on the bowl. Just google that number to check it out. Its just a simple way to be sure youve got what you need before you start fixing it like I did having a v8 carb on my 4cyl(it was like that when I bought, I swear)
 

KaGee

Admiral
Joined
Aug 14, 2004
Messages
7,069
Re: Rochester 2GV tuning

FYI, my factory manual says to START out by having both screws 2 1/2 turns out and fine tuning from there. Your engine should idle at that setting. Also, proper idle mixture is set while the boat is in the water under power.
 

Gary H NC

Fleet Admiral
Joined
Dec 1, 2005
Messages
8,972
Re: Rochester 2GV tuning

Yep,the 2 1/2 turns out is a good starting point.
Before adjusting the idle mixture the timing and dwell MUST be set to specs.
As well as all other tune up things complete.
When i tuned my Rochester carb it ended up being about 2 1/4 turns out to get it right. Every carb and engine is different..
 

turpehar

Cadet
Joined
Jul 25, 2007
Messages
26
Re: Rochester 2GV tuning

Thanks for all your help. I've been on vacation and using the boat at 2 turns out on the two screws. It seems that I use a lot of fuel for what I'm doing. However, not ever having a boat before, plus my handful of times riding in a boat, I have no gauge for how much fuel to expect to burn. Mostly I've just been riding around on a small lake. The last few days we've done some tubing.
I did turn the screws in to 1 1/2 but then the idle went bad. Turned them back out and it came back out of it.

So, for like three hours of boating I'm using like 8-9 gallons of fuel. It this normal?

Thanks again
 
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