Calling all carb tuners (bog on acceleration)

[phil]

Today, I went out with my brother on the 82 Skier. Started fine, ran fine..for a while.. All the sudden when we would try and accelerate a little bit harder when pulling up a skier the engine would start to bog down. This has never happened before.  So I opened the engine cover and had my bro nail it and it bogged again... I noticed that the throttle plates are not opening. At least not enough that is visble to my eye when crusing on the lake. I had him do a few accelerations and when I tried to manually open the secondaries with my hand by turning the rod attached to the secondaries it would run fine.

Two things, shouldn't the primary (one with the choke above right?) butterfly open all the way and not just crack open when you are running full throttle? Also, even when I would use my hand and open the secondary a little bit it never would open all the way just a little bit.  But when I did this to the secondary it seemed to have fixed the bogging issue and accelerated hard and normal. 

It's an 82 Skier  351w with the holley 4160 and as far as I know it carb is original. 

Any suggestions?

[phil]

Also, are these 4160's 600 cfm or 650?

[Mike Harry]

There are two types of carb guys (that I have noticed). Ones that can rebuild a carb if its not running right and ones that can tell you why it isnt running right in the first place.

I wish I could help you, but I am the first kind. I can rebuild them all day long and make them work right, but diagnosing is not really my deal....... (although I could tell you if I tore it down) if that makes any since whatsoever.

[Midskier]

Mike, I don't want to be either right now, Phil I should be off the water by 9am tomorrow
give me shout and maybe I can point you in the right direction

Dan T
219-365-1466

[phil]

Well, I took some carb cleaner to her, and retuned the idle air mixture, and she's running like a raped ape. Not sure what the problem was but I couldn't reproduce it yesterday on the lake. I had the flame arrestor off and I could see the accel pump shoot fuel, and also watched all 4 barrels open so she seems to be running correctly. I still think I need to just do a rebuild since I don't think it's ever been done on this carb before.

[Joel]

Sounds like some of the linkage was gummed up... and the carb cleaner did its job.  If it isnt broke - DONT FIX IT!!!   

[phil]

Damn, my bro told me that It cut out again today while he was out on the lake. Accelerates about normal to 2800RPM or so then it starts chugging and won't go past......

[Pelvic Woo]

I had a very similar problem early on in the season...a bottle of Gumout did the trick.  Was told that the higher level of ethanol that is in today's gas is the culprit.  Apparently ethanol can eat away at the plastic gas tank and create a jelly like substance that can seriously effect your fuel system.  Sta Bil makes a product designed to prevent this from occurring in marine applications.  I don't know though...does anyone else have any ideas?

[phil]

It would makes sense for it to be the carb gummed up somewhere..... When I kept the boat at my house I would always run ethanol free gas and that's not the case any more. However, the tank in our 82 is aluminum or some type of metal. I think I'm going to bring the carb to an engine builder and have them rebuild it..

[daveo]

Just a suggestion but have you checked the small check valve at the fuel tank outlet? I have a 87 advance and at the beginning of this season i had a problem similar to yours. I changed fuel pump,had carb rebuilt,changed all the fuel lines and still had the problem. Finally (and by mistake) I found the check valve at the outlet on the fuel tank. Its a small ball bearing and a spring inside the elbow at the top of the fuel tank. Mine was all corroded and gunked up. After removing it the Problem was solved! $400.00 later and it was a no $fix. Just something to check before you spend alot of money on nothing


                                                                                                                      daveo

[Joel]

Daveo,

Where is it located??  At the top port side /front... stbd side / front... where exactly???  Thanks!

[Midskier]

it's called an anti siphon valve it is the barbed fitting the fuel hose connects to @ the fuel tank, take the fuel hose off, un-thread the fitting from the elbow and inspect it
it's been mentioned several times on this board

good luck
Dan T

[daveo]

Dan,
    I removed the anti siphon  valve (thanks for the correct name). Am I going to have any problems running without it?

[phil]

So we had the carb rebuilt by a reputable speed shop. My brother took it out and said it's running better than ever. I will check it out for myself later this week. I guess the guy said that their was a torn diaphragm in it.

[Mike Harry]

Come on Phil! Exactly what I said..... if it aint working right, rebuild it 

Thats always my answer on a carb problem cause I can never tell whats wrong till I get in there.