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View Full Version : got a carb question, also tstat PCM


strad
09-30-2012, 02:05 PM
1984 SS. So far I've only run it on the trailer (bought it after a prop strike as some of you might remember). What I've discovered is that with the throttle pulled back to neutral position it doesn't want to idle. It needs a little throttle to keep running, and the tach will show about 800 rpms with a little bit of throttle. I'm prepared to take it out on the lake like that just to see if it straightens itself out (hasn't been run on the water for about a year).

But I'd like to have this carb identified. I don't know where to look for a model number. Don't see one anywhere, so all I know for sure is that it is a Holley lol.
http://i829.photobucket.com/albums/zz212/mgheffner/DSCN2677.jpgand
http://i829.photobucket.com/albums/zz212/mgheffner/DSCN2675.jpg

I did not run it long enough to have the tstat open. I got a lot of (dirty) water out the exhaust right when I started it up, but then after running a minute or so I was only getting a little bit (running on fake a lake). I did verify that the raw water pump was pumping water out by removing the top hose and running it just long enough to get some flow out of it. It's a new impeller, and I did lube it with some dish soap before firing it up. So the question is, might I have a flow problem or am I ok so far? How much water typically will exit each exhaust at idle speeds? Before the tstat opens that is.
Edit: I was just going to pull/replace the tstat just for maintenance. How many tstats do I have? I know some engines have more than one. . .

On another note, man that's a good sound lol!

keith3613
09-30-2012, 02:23 PM
I also have a 1984 S&S. Water comes out of the exhaust constantly. The water goes through the engine to keep it cool. Then, the water also travels inside a wall in the exhaust manifolds to keep them cool and pre-heat them so you don't get condensation on the outside (prevents rust, etc). Your carburetor is a Holley 600 (for a 351 Ford Engine). They are common and skidim.com has everything for them.

strad
09-30-2012, 02:38 PM
Well I don't think I'm getting enough out the exhaust then. Where might I start looking for an obstruction? I guess I don't understand all the paths water might take to get to the exhaust. I see those two lines that come off the tstat housing and run to the exhaust manifolds, and I see the raw water pump supply to the tstat housing, which comes in right next to where the two lines to the manifolds exit. Before the stat opens can water take a direct path from one to the other?

JimN
09-30-2012, 02:41 PM
1984 SS. So far I've only run it on the trailer (bought it after a prop strike as some of you might remember). What I've discovered is that with the throttle pulled back to neutral position it doesn't want to idle. It needs a little throttle to keep running, and the tach will show about 800 rpms with a little bit of throttle. I'm prepared to take it out on the lake like that just to see if it straightens itself out (hasn't been run on the water for about a year).

But I'd like to have this carb identified. I don't know where to look for a model number. Don't see one anywhere, so all I know for sure is that it is a Holley lol.

I did not run it long enough to have the tstat open. I got a lot of (dirty) water out the exhaust right when I started it up, but then after running a minute or so I was only getting a little bit (running on fake a lake). I did verify that the raw water pump was pumping water out by removing the top hose and running it just long enough to get some flow out of it. It's a new impeller, and I did lube it with some dish soap before firing it up. So the question is, might I have a flow problem or am I ok so far? How much water typically will exit each exhaust at idle speeds? Before the tstat opens that is.
Edit: I was just going to pull/replace the tstat just for maintenance. How many tstats do I have? I know some engines have more than one. . .

On another note, man that's a good sound lol!

The patent numbers may help you find out which model the carb is.

I would start by verifying the timing advance before anything else partly because I don't know if you have done this and because it takes almost no time to do it. If it's a 6-10 (depoending on the correct spec), move on to the carb. Get it to the lowest idle speed and if you can get a vacuum gauge, connect that to the vacuum port and watch it as you adjust the mixture screw. When it's pulling maximum vacuum, try to lower the idle speed to 650RPM.

As Thrall's tagline indicates, I'm not a fan of the Fake A Lake. It's way too easy for it to slip on the hull when someone moves in a boat- I would rather see a garden hose connected to the raw water hose, but only if the water volume and pressure are high enough to keep from starving the raw water pump. Using a hose dipped in bucket or a container that's larger allows idle without running out of water and it also lets you run it higher than idle for as long as the water lasts.

strad
09-30-2012, 02:48 PM
Well I guess I better run it from a bucket then before I freak out. That's what the seller did before I bought it to verify that it runs. And it sucked the water down just fine. I was just uncomfortable the first time after changing the impeller 'cause I didn't see a way that I could get water from the bucket to the pump before starting it. But there's water at the pump now.

Cloaked
09-30-2012, 03:12 PM
Well I guess I better run it from a bucket then before I freak out. That's what the seller did before I bought it to verify that it runs. And it sucked the water down just fine. I was just uncomfortable the first time after changing the impeller 'cause I didn't see a way that I could get water from the bucket to the pump before starting it. But there's water at the pump now.A water hose into the top of the trannsmission cooler. Slip joint pliers are there to wedge the nozzle open. Been doing this for many years. Your mileage and preference may vary.

$0.02

I changed out the horizontal configuration of the cooler on a 93 model and mounted it vertical (same position as shown below on the 85 model) as well. Much easier than a bucket as far as I am concerned. Water flow is what it is. Can't be any more than what a hose can keep a bucket supplied.

.

strad
10-01-2012, 01:15 PM
Update: well I was reading the correctcraft forum and I have determined that the carb is a 4160. It is Holley list number 75009-1 (this number is found on the choke horn, and is how I determined that the carb is a 4160). It is possible that I have an idle circuit issue, but it'll have to wait until this weekend to figure it out. Gotta buy a timing light and a vacuum gauge. Up to now I've only worked on efi cars, where those tools are not usually necessary.

My guess would be that the carb is gummed up from sitting. The carb looks way too clean on the outside to have not been rebuilt at least once.

thatsmrmastercraft
10-01-2012, 01:28 PM
Once you have verified the timing as JimN suggested, and if you have any difficulties getting the RPM down to an acceptable number, you may have some gunk in the idle circuit. To clean out the idle mixture passages remove the mixture screws and insert the straw from a can of carb cleaner and spray them until there is good flow. Install the mixture screws until lightly seated, them back out 1 1/2 turns and try adjusting again.

cbryan70
10-01-2012, 02:47 PM
What is wrong with the thing idling at 800 especially when its not up to temp?

pkskier
10-01-2012, 03:05 PM
That is a 4160 carb and it is not the original, it has been replaced at some point due to the vacuum line that is plugged with the rubber cap.

JimN
10-01-2012, 03:21 PM
Update: well I was reading the correctcraft forum and I have determined that the carb is a 4160. It is Holley list number 75009-1 (this number is found on the choke horn, and is how I determined that the carb is a 4160). It is possible that I have an idle circuit issue, but it'll have to wait until this weekend to figure it out. Gotta buy a timing light and a vacuum gauge. Up to now I've only worked on efi cars, where those tools are not usually necessary.

My guess would be that the carb is gummed up from sitting. The carb looks way too clean on the outside to have not been rebuilt at least once.

If the boat is from your area, a clean carb isn't out of the question. One thing that really screwed up the way one of my cars ran was a bad accelerator pump diaphragm. With ethanol thrown into the mix of possible causes, I would definitely check into that, too.

If you have an O'Reiley, Autozone or some other auto parts dealers, use theirs- they have a loaner program.

VRS Fan
10-01-2012, 04:07 PM
All good advice here. Sometimes it can be running too rich at idle due to drops of fuel coming out of those little barrel things in each large barrel. Sorry forgot the technical term for those things. Anyway when it is running near idle look down each barrel (all 4 of them) and make sure there is no drops of fuel ever coming out of them.

strad
10-01-2012, 05:17 PM
What is wrong with the thing idling at 800 especially when its not up to temp?

Well, the problem I see is that it doesn't want to idle until significantly past the point at which the transmission engages into gear (of course I've got the transmission interlock pulled out so it won't go into gear on the trailer). I'd like to at least solve that issue before taking up ramp time lol. The learning curve is steep in too many areas right now. I'm at least confident I can back the trailer straight into the water though.

@ JimN, the boat is a lifelong SF bay area/Delta boat prior to my purchase. It has been garage kept its entire life.

Cloaked
10-01-2012, 05:48 PM
...........guess would be that the carb is gummed up from sitting. The carb looks way too clean on the outside to have not been rebuilt at least once.I have seen carbs that clean from years of service. A rebuild is not much more than a set of gaskets and a few internal parts.

My opinion is to put a new carb on there and know what you have. It's only 28 years old.... I used to fool with rebuilds but then it seemed I noticed a trend that about every three years, I was back to square one, etc.... A new 4160 will run you about $525 US. I don't like dropping a lot of dough on a part but it's a known baseline for me.

If you rebuild the carb, soaking it is the most important part. There is where it either will clean up nicely or continue to be gummed up. Let it soak for 24 hours min. Keep the solution agitated frequently as best you can. Then let it sit for the last 12 hours of so. Disassemble cautiously with jets, power valve, and gentle on the floats and bowl.

One thing I learned a long time ago is to loosen the fitting at the fuel line to the carb. Do not try and wiggle it out. Unbolt the carb and lift it off of the spacer plate and importantly off of the fitting.

Jim's point about the fuel pump is also a consideration. A new fuel pump for about $75 US is worth having.

.

strad
10-02-2012, 09:13 PM
Well I did get it to settle down to a nice idle today. And it idles with the throttle in the neutral position. Tach indicates 800-1000 rpms but it actually doesn't sound to me like it's spinning that fast. Is there an error with these tachs? It also got up to about 150 degrees indicated on temp and stabilized there. Plenty of water out the exhaust too, and risers are cool to the touch. So I'm going to drain and fill the trans fluid between now and the weekend and then we'll go put it in the lake and see what happens (fingers crossed lol). My water hoses are not in beautiful shape, but I think they'll work until I get around to measuring and ordering.

Edit: oh, and Cloaked, JimN was actually talking about the accelerator pump, not the fuel pump. I don't fully understand how it works, but it is on the carb, and I know the engine won't rev very well or at all if it's gone bad. This one revs just fine.

Cloaked
10-02-2012, 09:47 PM
Well I did get it to settle down to a nice idle today. And it idles with the throttle in the neutral position. Tach indicates 800-1000 rpms but it actually doesn't sound to me like it's spinning that fast. Is there an error with these tachs? It also got up to about 150 degrees indicated on temp and stabilized there. Plenty of water out the exhaust too, and risers are cool to the touch. So I'm going to drain and fill the trans fluid between now and the weekend and then we'll go put it in the lake and see what happens (fingers crossed lol). My water hoses are not in beautiful shape, but I think they'll work until I get around to measuring and ordering.

Edit: oh, and Cloaked, JimN was actually talking about the accelerator pump, not the fuel pump. I don't fully understand how it works, but it is on the carb, and I know the engine won't rev very well or at all if it's gone bad. This one revs just fine.Your report of the engine is all in order, temp etc.

Acknowledge the acc pump. Spoke before I thought.

Good luck.

.

JimN
10-02-2012, 09:52 PM
Well I did get it to settle down to a nice idle today. And it idles with the throttle in the neutral position. Tach indicates 800-1000 rpms but it actually doesn't sound to me like it's spinning that fast. Is there an error with these tachs? It also got up to about 150 degrees indicated on temp and stabilized there. Plenty of water out the exhaust too, and risers are cool to the touch. So I'm going to drain and fill the trans fluid between now and the weekend and then we'll go put it in the lake and see what happens (fingers crossed lol). My water hoses are not in beautiful shape, but I think they'll work until I get around to measuring and ordering.

Edit: oh, and Cloaked, JimN was actually talking about the accelerator pump, not the fuel pump. I don't fully understand how it works, but it is on the carb, and I know the engine won't rev very well or at all if it's gone bad. This one revs just fine.

The tach may be inaccurate- if you can find another way to see the RPM, you can check for accuracy. I have a multi-meter that also does dwell and tach- it cost about $20. This can happen when the base of the distributor needs to be cleaned- its ground reference is very important.

j.mccreight@hotmail.com
10-02-2012, 11:16 PM
The tach may be inaccurate- if you can find another way to see the RPM, you can check for accuracy. I have a multi-meter that also does dwell and tach- it cost about $20. This can happen when the base of the distributor needs to be cleaned- its ground reference is very important.

Also most cheapo timing lights from the auto parts also do rpm...

strad
10-03-2012, 12:18 AM
Also most cheapo timing lights from the auto parts also do rpm...

That's what I was hoping for. I hadn't checked into that yet, but I do need to buy a timing light. This certainly is a fun toy to play with!

j.mccreight@hotmail.com
10-03-2012, 01:42 AM
That's what I was hoping for. I hadn't checked into that yet, but I do need to buy a timing light. This certainly is a fun toy to play with!

Idle should be ~800 rpm in neutral so when the transmission is in gear the idle drops down to about ~600 rpm.

http://www.amazon.com/gp/aw/d/B002SSDUOA