More strange engine problems

The obvious answer is turn the adjustment screw in some more. But, does anyone have a procedure for adjusting the fast mixture? My engine is missing and changing RPM a few hundred which is very disconcerting. It clearly is not the alternator as the regulator is removed waiting for the new one. Rotor, cap, and points are new. Wires look excellent. I removed the plugs and I have never seen plugs so black so this is clearly the problem. Changing the fast mixture screw didn't fix the problem so I probably need new plugs before I adjust things. Which brings me to this list and the question of a process to adjust the carb. The fast mixture screw is out 1 3/4 turns, which I thought was correct but I guess it isn't. The carb is recently rebuilt, the engine can idol down lower than it ever has so something is right but black plugs are not good. This is an old 30hp Gray Marine gas engine. Allen

Allen, Black plugs indicate it is running rich. Replace/clean your plugs and make sure the air cleaner isn't clogged, start the engine and get it around 2000 RPM to ensure it is out of low idle and try turning the fast idle adjustment in until it smooths out. Keep count of your turns so you can put it back to where it was if it quits on you. Look at your exhaust; black exhaust means you are too rich and white exhaust means you're too lean. Another place to check is your vacuum advance to the distributor if you have one. I had an engine that 'hunted' at RPM once (on a car) and found a vacuum leak on the cracked rubber hose from the manifold to the distributor. I replaced the hose and it ran fine. I'm sure there are guys on the list that will be able to explain better what to check and possible solutions. Listen to Tom Vandiver and Joe DeMers if they pipe up. Good luck. Mike M. On 5/19/2010 10:52 AM, Allen Edwards wrote: > > > The obvious answer is turn the adjustment screw in some more. But, > does anyone have a procedure for adjusting the fast mixture? My > engine is missing and changing RPM a few hundred which is very > disconcerting. It clearly is not the alternator as the regulator is > removed waiting for the new one. Rotor, cap, and points are new. > Wires look excellent. I removed the plugs and I have never seen > plugs so black so this is clearly the problem. Changing the fast > mixture screw didn't fix the problem so I probably need new plugs > before I adjust things. Which brings me to this list and the question > of a process to adjust the carb. The fast mixture screw is out 1 3/4 > turns, which I thought was correct but I guess it isn't. The carb > is recently rebuilt, the engine can idol down lower than it ever has > so something is right but black plugs are not good. This is an old > 30hp Gray Marine gas engine. > > __

Thanks for the reply, I guess what is bothering me is that I thought the fast mixture screw should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is obviously running extremely rich. By the way, when I look at the exhaust, all I see is water :-) Allen On Wed, May 19, 2010 at 8:33 AM, mike <mi… [at] wahini.org> wrote: > > > Allen, > Black plugs indicate it is running rich. Replace/clean your plugs and make > sure the air cleaner isn't clogged, start the engine and get it around 2000 > RPM to ensure it is out of low idle and try turning the fast idle adjustment > in until it smooths out. Keep count of your turns so you can put it back to > where it was if it quits on you. Look at your exhaust; black exhaust means > you are too rich and white exhaust means you're too lean. > Another place to check is your vacuum advance to the distributor if you > have one. I had an engine that 'hunted' at RPM once (on a car) and found a > vacuum leak on the cracked rubber hose from the manifold to the distributor. > I replaced the hose and it ran fine. I'm sure there are guys on the list > that will be able to explain better what to check and possible solutions. > Listen to Tom Vandiver and Joe DeMers if they pipe up. > Good luck. > Mike M. > > > On 5/19/2010 10:52 AM, Allen Edwards wrote: > > > > The obvious answer is turn the adjustment screw in some more. But, does > anyone have a procedure for adjusting the fast mixture? My engine is > missing and changing RPM a few hundred which is very disconcerting. It > clearly is not the alternator as the regulator is removed waiting for the > new one. Rotor, cap, and points are new. Wires look excellent. I removed > the plugs and I have never seen plugs so black so this is clearly the > problem. Changing the fast mixture screw didn't fix the problem so I > probably need new plugs before I adjust things. Which brings me to this > list and the question of a process to adjust the carb. The fast mixture > screw is out 1 3/4 turns, which I thought was correct but I guess it isn't. > The carb is recently rebuilt, the engine can idol down lower than it ever > has so something is right but black plugs are not good. This is an old 30hp > Gray Marine gas engine. > __ > > > >

Allen, If you are seeing only water from your exhaust and not different colors of smoke, then maybe your plugs were black from before the carb was rebuilt and they are very old. If that is the case, quit messing with the carb and check for vacuum leaks, loose or cracked spark plug wires (to include the boots). Check the wire terminals at your distributor to make sure they aren't corroded or making a bad connection You may have good voltage at the battery, but a corroded terminal can cause all sorts of weird problems. Insufficient spark voltage could also be a cause for black plugs. (I know you've been through the points, etc., but how about the ballast resistor, if you have one? Check those wires too. Good contact with the condenser? Maybe it vibrated loose. Who knows?) I'm curious how it goes.... Mike On 5/19/2010 11:49 AM, Allen Edwards wrote: > > > Thanks for the reply, > > > I guess what is bothering me is that I thought the fast mixture screw > should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine > is obviously running extremely rich. By the way, when I look at the > exhaust, all I see is water :-) > > Allen

I mean no offense, but if you have wires that have been cut, twisted together and electrical taped like so many boats of our vintage (wrongly!) do, open up the tape and check for corroded wires. Please ignore if this doesn't apply. Mike On 5/19/2010 1:06 PM, mike wrote: > > > Allen, > If you are seeing only water from your exhaust and not different > colors of smoke, then maybe your plugs were black from before the carb > was rebuilt and they are very old. If that is the case, quit messing > with the carb and check for vacuum leaks, loose or cracked spark plug > wires (to include the boots). Check the wire terminals at your > distributor to make sure they aren't corroded or making a bad > connection You may have good voltage at the battery, but a corroded > terminal can cause all sorts of weird problems. Insufficient spark > voltage could also be a cause for black plugs. (I know you've been > through the points, etc., but how about the ballast resistor, if you > have one? Check those wires too. Good contact with the condenser? > Maybe it vibrated loose. Who knows?) I'm curious how it goes.... > Mike > > On 5/19/2010 11:49 AM, Allen Edwards wrote: > >> >> >> Thanks for the reply, >> >> >> I guess what is bothering me is that I thought the fast mixture screw >> should be out 2 to 3 turns and I have it out only 1 3/4 yet the >> engine is obviously running extremely rich. By the way, when I look >> at the exhaust, all I see is water :-) >> >> Allen >

I love getting more things to check, really I mean it. I think I will list some of the things I have checked: 1) Voltage at the coil is 12.55. Remember, no voltage regulator for the moment so this is a good reading 2) Plug wires look new and are relatively new 3) No vacuum lines on this engine 4) I would guess there is exhaust in there somewhere but I can't see it for all the water. I guess this means the air fuel ratio is above some magic number which would be very rich indeed where the exhaust is black soot. Things I will check 1) Spark timing 2) Wiring to the coil check for intermittent connection. 3) New plugs and hopefully someone will tell me a good way to set the mixture, which was my question. Allen On Wed, May 19, 2010 at 10:06 AM, mike <mi… [at] wahini.org> wrote: > > > Allen, > If you are seeing only water from your exhaust and not different colors of > smoke, then maybe your plugs were black from before the carb was rebuilt and > they are very old. If that is the case, quit messing with the carb and check > for vacuum leaks, loose or cracked spark plug wires (to include the boots). > Check the wire terminals at your distributor to make sure they aren't > corroded or making a bad connection You may have good voltage at the > battery, but a corroded terminal can cause all sorts of weird problems. > Insufficient spark voltage could also be a cause for black plugs. (I know > you've been through the points, etc., but how about the ballast resistor, if > you have one? Check those wires too. Good contact with the condenser? Maybe > it vibrated loose. Who knows?) I'm curious how it goes.... > Mike > > > On 5/19/2010 11:49 AM, Allen Edwards wrote: > > > > Thanks for the reply, > > I guess what is bothering me is that I thought the fast mixture screw > should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is > obviously running extremely rich. By the way, when I look at the exhaust, > all I see is water :-) > > Allen > > >

I was just told that the adjustment should be out 2-3 turns so perhaps I screwed up when I rebuilt it. In any event, the adjustment procedure was to screw it in until it starts to kill and back off 1/4 turn. If I have a bad washer on the seat and there is a leak there, I guess I can compensate by adjusting the mixture screw... This should be done with new plugs. If anyone knows more about these carbs, please feel free to let me know what you think. Allen On Wed, May 19, 2010 at 11:45 AM, Allen Edwards <al… [at] gmail.com>wrote: > I love getting more things to check, really I mean it. I think I will list > some of the things I have checked: > 1) Voltage at the coil is 12.55. Remember, no voltage regulator for the > moment so this is a good reading > 2) Plug wires look new and are relatively new > 3) No vacuum lines on this engine > 4) I would guess there is exhaust in there somewhere but I can't see it for > all the water. I guess this means the air fuel ratio is above some magic > number which would be very rich indeed where the exhaust is black soot. > > Things I will check > 1) Spark timing > 2) Wiring to the coil check for intermittent connection. > 3) New plugs and hopefully someone will tell me a good way to set the > mixture, which was my question. > > Allen > > > On Wed, May 19, 2010 at 10:06 AM, mike <mi… [at] wahini.org> wrote: > >> >> >> Allen, >> If you are seeing only water from your exhaust and not different colors of >> smoke, then maybe your plugs were black from before the carb was rebuilt and >> they are very old. If that is the case, quit messing with the carb and check >> for vacuum leaks, loose or cracked spark plug wires (to include the boots). >> Check the wire terminals at your distributor to make sure they aren't >> corroded or making a bad connection You may have good voltage at the >> battery, but a corroded terminal can cause all sorts of weird problems. >> Insufficient spark voltage could also be a cause for black plugs. (I know >> you've been through the points, etc., but how about the ballast resistor, if >> you have one? Check those wires too. Good contact with the condenser? Maybe >> it vibrated loose. Who knows?) I'm curious how it goes.... >> Mike >> >> >> On 5/19/2010 11:49 AM, Allen Edwards wrote: >> >> >> >> Thanks for the reply, >> >> I guess what is bothering me is that I thought the fast mixture screw >> should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is >> obviously running extremely rich. By the way, when I look at the exhaust, >> all I see is water :-) >> >> Allen >> >> >> > >

Allen, I do not know the details of your carb. If it has a bowl with a float to control the fuel level in the bowl which will control the rich/lean setting. The shut off needle could be sticking or leaking causing erratic fuel flow from rich when the fuel level is high to lean when the fuel level is low. Just my thought. Bert Pesak

Be sure your needle and floatvalve and seat are not leaking and the fuel level in the carb is what contributes to the rich mix. From: Allen Edwards <al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com Sent: Wed, May 19, 2010 8:49:22 AM Subject: Re: [Cal_Boats] More strange engine problems Thanks for the reply, I guess what is bothering me is that I thought the fast mixture screw should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is obviously running extremely rich. By the way, when I look at the exhaust, all I see is water :-) Allen On Wed, May 19, 2010 at 8:33 AM, mike <mi… [at] wahini.org> wrote: >Allen, >Black plugs indicate it is running rich. Replace/clean your plugs and make sure the air cleaner isn't clogged, start the engine and get it around 2000 RPM to ensure it is out of low idle and try turning the fast idle adjustment in until it smooths out. Keep count of your turns so you can put it back to where it was if it quits on you. Look at your exhaust; black exhaust means you are too rich and white exhaust means you're too lean. >Another place to check is your vacuum advance to the distributor if you have one. I had an engine that 'hunted' at RPM once (on a car) and found a vacuum leak on the cracked rubber hose from the manifold to the distributor. I replaced the hose and it ran fine. I'm sure there are guys on the list that will be able to explain better what to check and possible solutions. Listen to Tom Vandiver and Joe DeMers if they pipe up. >Good luck. >Mike M. > > >On 5/19/2010 10:52 AM, Allen Edwards wrote: > >>The obvious answer is turn the adjustment screw in some more. But, does anyone have a procedure for adjusting the fast mixture? My engine is missing and changing RPM a few hundred which is very disconcerting. It clearly is not the alternator as the regulator is removed waiting for the new one. Rotor, cap, and points are new. Wires look excellent. I removed the plugs and I have never seen plugs so black so this is clearly the problem. Changing the fast mixture screw didn't fix the problem so I probably need new plugs before I adjust things. Which brings me to this list and the question of a process to adjust the carb. The fast mixture screw is out 1 3/4 turns, which I thought was correct but I guess it isn't. The carb is recently rebuilt, the engine can idol down lower than it ever has so something is right but black plugs are not good. This is an old 30hp Gray Marine gas engine. >>__ >

I guess I am pulling the carb and checking a few things. I know the float valve is not stuck open because that fills the bilge with gas until you hit the carb with a hammer. That isn't happening. However, perhaps it is leaking. Allen On Wed, May 19, 2010 at 2:43 PM, mike farrell <ve… [at] yahoo.com> wrote: > > > Be sure your needle and floatvalve and seat are not leaking and the fuel > level in the carb is what contributes to the rich mix. > > ------------------------------ > *From:* Allen Edwards <al… [at] PaloAltoPhoto.com> > *To:* Ca… [at] yahoogroups.com > *Sent:* Wed, May 19, 2010 8:49:22 AM > > *Subject:* Re: [Cal_Boats] More strange engine problems > > > > Thanks for the reply, > > I guess what is bothering me is that I thought the fast mixture screw > should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is > obviously running extremely rich. By the way, when I look at the exhaust, > all I see is water :-) > > Allen > > On Wed, May 19, 2010 at 8:33 AM, mike <mi… [at] wahini.org> wrote: > >> >> >> Allen, >> Black plugs indicate it is running rich. Replace/clean your plugs and make >> sure the air cleaner isn't clogged, start the engine and get it around 2000 >> RPM to ensure it is out of low idle and try turning the fast idle adjustment >> in until it smooths out. Keep count of your turns so you can put it back to >> where it was if it quits on you. Look at your exhaust; black exhaust means >> you are too rich and white exhaust means you're too lean. >> Another place to check is your vacuum advance to the distributor if you >> have one. I had an engine that 'hunted' at RPM once (on a car) and found a >> vacuum leak on the cracked rubber hose from the manifold to the distributor. >> I replaced the hose and it ran fine. I'm sure there are guys on the list >> that will be able to explain better what to check and possible solutions. >> Listen to Tom Vandiver and Joe DeMers if they pipe up. >> Good luck. >> Mike M. >> >> >> On 5/19/2010 10:52 AM, Allen Edwards wrote: >> >> >> >> The obvious answer is turn the adjustment screw in some more. But, does >> anyone have a procedure for adjusting the fast mixture? My engine is >> missing and changing RPM a few hundred which is very disconcerting. It >> clearly is not the alternator as the regulator is removed waiting for the >> new one. Rotor, cap, and points are new. Wires look excellent. I removed >> the plugs and I have never seen plugs so black so this is clearly the >> problem. Changing the fast mixture screw didn't fix the problem so I >> probably need new plugs before I adjust things. Which brings me to this >> list and the question of a process to adjust the carb. The fast mixture >> screw is out 1 3/4 turns, which I thought was correct but I guess it isn't. >> The carb is recently rebuilt, the engine can idol down lower than it ever >> has so something is right but black plugs are not good. This is an old 30hp >> Gray Marine gas engine. >> __ >> >> >> > > > >

Gas engines are fun. If the float level is too high then vibrations can create fuel mixture problems. New/worn adjustment needles allow fuel to flow, but the 1,2,3 turns rule can change... The jet needle on the float can be sticky or sprung wrong creating a float problem I purchased a "Clear" spark plug so I could look at the flame color on my old gray marine. The plug is called a Gunson Colortune. Purchase: http://www.autoexpertproducts.com/colortune-14mm.htm Video : http://www.youtube.com/watch?v=_afOM88lk9E&NR=1 [cid:image003.jpg@01CAF769.51E7E860] From: Ca… [at] yahoogroups.com [mailto:Ca… [at] yahoogroups.com] On Behalf Of mike farrell Sent: Wednesday, May 19, 2010 2:44 PM To: Ca… [at] yahoogroups.com Subject: Re: [Cal_Boats] More strange engine problems Be sure your needle and floatvalve and seat are not leaking and the fuel level in the carb is what contributes to the rich mix. From: Allen Edwards <al… [at] PaloAltoPhoto.com> To: Ca… [at] yahoogroups.com Sent: Wed, May 19, 2010 8:49:22 AM Subject: Re: [Cal_Boats] More strange engine problems Thanks for the reply, I guess what is bothering me is that I thought the fast mixture screw should be out 2 to 3 turns and I have it out only 1 3/4 yet the engine is obviously running extremely rich. By the way, when I look at the exhaust, all I see is water :-) Allen On Wed, May 19, 2010 at 8:33 AM, mike <mi… [at] wahini.org<mailto:mi… [at] wahini.org>> wrote: Allen, Black plugs indicate it is running rich. Replace/clean your plugs and make sure the air cleaner isn't clogged, start the engine and get it around 2000 RPM to ensure it is out of low idle and try turning the fast idle adjustment in until it smooths out. Keep count of your turns so you can put it back to where it was if it quits on you. Look at your exhaust; black exhaust means you are too rich and white exhaust means you're too lean. Another place to check is your vacuum advance to the distributor if you have one. I had an engine that 'hunted' at RPM once (on a car) and found a vacuum leak on the cracked rubber hose from the manifold to the distributor. I replaced the hose and it ran fine. I'm sure there are guys on the list that will be able to explain better what to check and possible solutions. Listen to Tom Vandiver and Joe DeMers if they pipe up. Good luck. Mike M. On 5/19/2010 10:52 AM, Allen Edwards wrote: The obvious answer is turn the adjustment screw in some more. But, does anyone have a procedure for adjusting the fast mixture? My engine is missing and changing RPM a few hundred which is very disconcerting. It clearly is not the alternator as the regulator is removed waiting for the new one. Rotor, cap, and points are new. Wires look excellent. I removed the plugs and I have never seen plugs so black so this is clearly the problem. Changing the fast mixture screw didn't fix the problem so I probably need new plugs before I adjust things. Which brings me to this list and the question of a process to adjust the carb. The fast mixture screw is out 1 3/4 turns, which I thought was correct but I guess it isn't. The carb is recently rebuilt, the engine can idol down lower than it ever has so something is right but black plugs are not good. This is an old 30hp Gray Marine gas engine.