Cold blooded 5.7l in lieu of coil replacement....

[burtonrider11]

Wow thanks for taking the time to post these. Here is where I am confused. I see the settings for the carb above, to make it lean, the choke adjustment goes to the right, rich, to the left. In the MerCruiser manual, it says the opposite. Yet, it the same manual, under settings, it says the normal setting is two mark to the right of center and it says this is lean. So the manual contradicts itself...

http://boatinfo.no/lib/mercruiser/manuals/mercruiser17.html#/448

http://boatinfo.no/lib/mercruiser/manuals/mercruiser17.html#/440

I guess at this point, I just need to know which way is truly lean and which way is rich

 

[ihc1470]

Loosen the screws that hold the choke thermostat in place and turn it and see which direction it has to go to open the choke plate as that is lean. Most do go clock wise for lean but not all.

 

[burtonrider11]

Eureka! I think I am headed in the right direction! Last night, I pulled the thermostat cover off and discovered that the spring inside or the tab the controls the choke plate are out of alignment. So basically, when I would adjust the thermostat previously, it was having absolutely no effect because the spring/coil wasn't even close to the tab.

So after playing with it, I can rotate the cover around so that it DOES alter the choke plate. I see that there is a screw inside that attaches the tab to the choke plate. Should I try to adjust the tab to meet up with the thermostat coil? Or should I just forego that and simply rotate the thermostat cover until I get the 1/8" opening that BT referenced above? I am kind of thinking I can adjust the tab somewhat, to at least get it close. The scribe marks probably won't be real accurate, but at least I will have some adjustment. This also explains why this boat always started easier with something holding the plate open....otherwise, I was trying to start it with the plate completely shut....Any help on what I hope will be the final adjustment would be greatly appreciated!

Oh, and for the record, either this is a different carb or the Merc Manual is wrong. Moving the adjuster clockwise DOES make it more lean, the merc manual says opposite...

 

[ihc1470]

Could you by chance post a picture of this tab your talking about? I am thinking what your referring to is the tang that sticks out that the spring is suppose to hit and move the choke plate but I am not certain. Is yours a sit up similar to fig 5 in the pictures I posted? If that is correct then that really is not supposed to be adjusted. There is an adjustment for the choke pull off which is the little brass piston that also connects to that lever assembly. You bend the external linkage to make that correct adjustment. Then you turn the thermostat housing to get the tension to close the choke. There are several possible things that are going on here, one being a wrong thermostat housing, another possibility is a wrong carb for the application, which might explain differences in what your seeing to what the book says. That is the reason I asked for the GM carb number and not the Mercruiser number or the rebuilders number. My experience and this comes from the auto side of things is most renewed carbs are not all they are cracked up to be. Most are not sit up correctly so the choke systems do not work correctly etc. If at all possible I always try to repair the carb that came on the engine. I realize you do not have that option so you need to work with what you have. But if the carb is adjusted to the specs that GM Rochester design it to operate at then you will have a much better chance of things working like they should.

For instance the 2 barrel on my engine the choke closes tight and the few times that I have started the engine while working getting things back in order it does what I would expect. That is it starts in a normal length of time and as soon as it does the choke opens enough that it is not flooding, which is the job of the choke pull off. Then as the engine continues to warm up the and the exhaust manifold builds heat the plate continues to open until it is vertical and out of the system for normal running conditions. If you were ever around a manual choke carb system you did the same thing when you pulled the choke knob out, you closed the choke plate tight and as soon as the engine started you pushed the knob back in to the point that the engine was not flooding and then as it warmed up you pushed the knob all the way back into the dash. You became the thermostat and pull off when operating the cable.

I know yours is an electrical choke. Does not change a thing on how it works the only thing it changes is the source of heat.

I am very happy that your starting to see progress and how the choke is suppose to work. Sounds like your just about there.

Dennis

 

[burtonrider11]

Thanks again Dennis, I'll try to grab some photos today or this weekend. The tab I am referring to is within the electric choke housing, it looks like this is connected via a screw to the choke plate itself. This is moved by the spring/coil on the thermostat. I could just leave everything as is within the housing and turn the thermostat housing until the correct adjustment is made IE setting it to 1/8" clearance/open when cold.

The only problem with this is that the scribe marks won't have any bearing anymore, but I am not sure if that's really a big deal, so long as the plate is open. I'll try to get a bunch of photos to illustrate everything.

I see what you are referring to with regard to the linkage, but what I am describing is all within the choke housing....

 

[burtonrider11]

Here are some photos:

http://i1053.photobucket.com/albums/s471/burtonrider11/IMG_3086_zpstbcg54wb.jpg

http://i1053.photobucket.com/albums/s471/burtonrider11/IMG_3087_zpsbjlg6p38.jpg

Here is a sequence showing rotation of the thermostat moving the choke plate, note it has to rotate nearly 180 degrees to start making adjustments.

http://i1053.photobucket.com/albums/s471/burtonrider11/IMG_3090_zpsvpabxco3.jpg

http://i1053.photobucket.com/albums/s471/burtonrider11/IMG_3089_zpshgsuuqqu.jpg

http://i1053.photobucket.com/albums/s471/burtonrider11/IMG_3088_zpsea3j9jbr.jpg

 

[ihc1470]

The pictures help some and yet no. So lets start with the carb number, what is it? You should find it below the fuel inlet fitting stamped into the body. It certainly does look like a Rochester 2GC or 2GV carb. Next can you post some over all pictures of the carb all for sides and more on level with the carb and not so much straight down. Maybe put some white paper or something around the carb to block some of the engine. All that shiny black makes it a little hard to see. What I am really looking for is the choke pull off system. I can not see it in the pictures you have up. The one your showing the tab and saying this is where the choke its shows the piston bore but no piston. The lever has no place to attach the piston to either. May not mean a thing as it may be a blank piston bore in other words no vacuum passage. That also means there should be a vacuum pull some where else on the carb and I am not seeing it. I took a few minutes and looked at my carb this morning. On mine it takes about 90 degrees of rotation from the time the choke plate just starts to close until it just seats. Then it looked like maybe another 1/2 inch of travel before the line on the cover lined up with the index mark on the housing. The choke plate is totally closed at that point. The index marks on mine are located about 3 o:clock yours appear to be about 12. All that really means is there were a lot of build variations for these carbs depending on application. I am lucky I know the history of the engine in my boat and the fact it is still as it came from the factory, Your dealing with a few unknowns at this point. Since your dealing with a rebuilt carb anything is possible until you get it sorted out. One suggestion might be to see if you could find a new or known good choke thermostat cover and compare with yours to see where the end of the lever is in relationship to the index mark. Again you will need the carb number to make sure your getting the correct item. Napa or some of the other parts chains might be able to help you out or a shop the deals with carbs. Unfortunately carbs are a thing of the past so parts are seldom sitting on a shelf any longer.

The other suggestion is get up on EBay type in Rochester 2GV marine and see what pictures look like yours. There are a few listed and the pictures are pretty good so it might also help in trying to determine just what it is you have.

 

[NHGuy]

BR & IHC check your pm boxes in a bit I am sending you the right info to diag & repair this.

 

[ihc1470]

NHGuy thanks for the link to the manual. Interesting to look at and I must say I can not find anything at all that looks like a choke pull off. That is i believe a first for me on an auto choke type carb but never to old to learn something new. The other thing I find interesting it looks as if they only use one idle mixture screw. Again strange for a 2 barrel. Burtonrider11 I have to believe the manual has a misprint on page 5B-9. At the top they say lean is to the left (c) and rich is to the right (b) when they show the choke thermostat housing, yet below it they are showing checking the choke unloader sitting of .080 and measuring at the top of the choke plate. That tells me the choke lever must go clock wise to open the choke is that correct? I have not looked back through your post but seems like you mentioned that you thought it was backwards too. I see in the specs it calls for 2 notches lean so that is where I would start and go from there, I hope I did not miss lead you to much, I think with the information NHGuy provided you should be able to sort it out. Let us all know your outcome. Dennis

 

[burtonrider11]

NHGuy thanks for the link to the manual. Interesting to look at and I must say I can not find anything at all that looks like a choke pull off. That is i believe a first for me on an auto choke type carb but never to old to learn something new. The other thing I find interesting it looks as if they only use one idle mixture screw. Again strange for a 2 barrel. Burtonrider11 I have to believe the manual has a misprint on page 5B-9. At the top they say lean is to the left (c) and rich is to the right (b) when they show the choke thermostat housing, yet below it they are showing checking the choke unloader sitting of .080 and measuring at the top of the choke plate. That tells me the choke lever must go clock wise to open the choke is that correct? I have not looked back through your post but seems like you mentioned that you thought it was backwards too. I see in the specs it calls for 2 notches lean so that is where I would start and go from there, I hope I did not miss lead you to much, I think with the information NHGuy provided you should be able to sort it out. Let us all know your outcome. Dennis

Hi Dennis,

You are correct, I am quite sure the Merc manual is wrong as well. When I pulled apart my choke the other day, I played with it and there is no way other than turning it clockwise to make it lean and to reach the .080 setting they are speaking of.

Assuming everything else is correct in the manual, setting the choke two marks to the right should set the choke close to the .080 opening. I think I can adjust the check plate lever to get it close to this and then make the final adjustments.

As I mentioned earlier, the current settings were so far out of whack that when I did adjust the choke, it had absolutely no effect. I can't wait to make these adjustments to see if that doesn't help with starting!

 

[ihc1470]

Read the instructions again on the choke unloader adjustment. That setting is check with the throttle wide open. The purpose of that adjustment is to open the choke enough to start the engine if you flood it. With the throttle plates close (low idle) I would think the throttle plate will be close but I could be wrong as this is a little different carb than what I have run across before. Would be interesting to have it sitting in front of me to see what all I could learn. Dennis

 

[burtonrider11]

Read the instructions again on the choke unloader adjustment. That setting is check with the throttle wide open. The purpose of that adjustment is to open the choke enough to start the engine if you flood it. With the throttle plates close (low idle) I would think the throttle plate will be close but I could be wrong as this is a little different carb than what I have run across before. Would be interesting to have it sitting in front of me to see what all I could learn. Dennis

Thanks again for all the help Dennis. I did adjust the tang/tab that connected to the choke plate. I haven't done anything with the choke unloader, it does appear to work when I move the throttle forward. I can also adjust the choke plate via the adjustment on the side of the carb now. I realized that with the old setting, the coil/spring was set to keep the choke plate closed, it's no wonder it always needed to be held open....

We are getting closer to spring in the midwest, I am hoping to fire her up in the next few weeks, my target date is April 15th - Tax day What a better day to take my mind off paying my taxes I'll keep everyone posted on how this adjustment works, I am confident this will help.

 

[ihc1470]

Can not think of a better way to get past the tax day blues than to go boating. Being a farmer I had to have them in 1 March. Hope that choke gives you no more issues. Dennis

 

[burtonrider11]

I know you aren't supposed to keep reviving old posts, however, I wanted to follow up with everything. Yesterday, I pulled our boat out of storage after having made the adjustments to the choke plate tab and electric choke assembly. When I had done it, I just eyeballed the choke plate setting. Our boat has been winterized so I knew it may take a bit to prime the (mechanical) fuel pump, unfog the cylinders etc.So I gave the throttle a couple of pumps and gave it a shot. I was real easy the first minute, I wanted to build some oil pressure and let the engine wake up before she started. After maybe 5 very quick turns of the key, she sputtered. On the next she fired for a second. I gave her just a bit more throttle and she fired right up. Not only that, she fired up and ran PERFECT. No feathering the throttle to keep her going or anything, she ran perfect. I let temp come up, checked fluids and belts and shut her off to keep cleaning. I probably ran for about 10 minutes.

That was at about 10:00am. I wanted to try it once again to test, so at about 7:00pm (engine was cold), I tried again. One full pump of throttle, a little advance and woosh! The engine fired immediately! Since we bought the boat last year, I've never been able to get her to start quickly and consistently. Some days I would drain both batteries trying to get her started......

Bottomline, I want to thank everyone for their help and time in this. I was set to buy a new coil and hope that fixed the issue. Instead, I actually fixed it! A special thanks to Dennis (IHC1470), who supplied materials and lots of ideas to fix it. I could not be happier and more grateful for everyone's help here!

 

[ihc1470]

Hey have fun on the water this summer. That sounds great. I wonder if your fuel burn per hour might be a little better also now? Time will tell on that. Dennis