Thermostat housing hole.

[Sea Rider]

If the seats are the original factory installed, all 3 should rest leveled against the bottom, just check them if so. Seems previous owner tried to remove some and ended rounding the heads.

Forgot to mention that If you place the slow jet against a light source your eyes will pay you a visual trick, will see the middle jet being clogged, but that ain't so, a magnifying glass will confirm so LOL!

To clarify since a reasonable doubt was created, previous posted pics does't show the jet being fully inserted in the outside nozzle's tip, in which case the fuel will exit through the small and middle orifices at same time when the container is squeezed hard. Didn't want to modify the tip diam just for the pic sesion as use it to squirt thinner shots inside every posible carb orifice regardless of the diam they are.

Post 95 pic shows same jet screwed inside the nozzle's tip, exposed to a light source can see a perfectl clean and rounded orifice, poking it lightly with a very thin needle did the trick. This poking orifices with needles, only applies when cleaning extremely gunked slow jets and nozzles orifices specially when out of stock or NLA...

Happy Boating​

 

[Douglasdzaster]

If the seats are the original factory installed, all 3 should rest leveled against the bottom, just check them if so. Seems previous owner tried to remove some and ended rounding the heads.

Forgot to mention that If you place the slow jet against a light source your eyes will pay you a visual trick, will see the middle jet being clogged, but that ain't so, a magnifying glass will confirm so LOL!

To clarify since a reasonable doubt was created, previous posted pics does't show the jet being fully inserted in the outside nozzle's tip, in which case the fuel will exit through the small and middle orifices at same time when the container is squeezed hard. Didn't want to modify the tip diam just for the pic sesion as use it to squirt thinner shots inside every posible carb orifice regardless of the diam they are.

Post 95 pic shows same jet screwed inside the nozzle's tip, exposed to a light source can see a perfectl clean and rounded orifice, poking it lightly with a very thin needle did the trick. This poking orifices with needles, only applies when cleaning extremely gunked slow jets and nozzles orifices specially when out of stock or NLA...

Happy Boating. My magnifying glass has an extra piece that is very strong with a light. I was looking at the jets and I really messed them up. Looks like one is now bigger than the other as well . I confirmed they’re all 60 as well. I found them. Says they’re in stock where you told me to go last time. Will call in the morning and verify. $11 each. I have learned lessons that cost a lot more.​

 

[Douglasdzaster]

I don’t know how but my reply seems to have attached it self to your post.

 

[Douglasdzaster]

Got all the parts to finish now. New o rings, jets, main jet etc. Tomorrow I’m taking #2 to the machine guy to see about getting the main jet out without damaging anything. After that I’m going through them one at the time again and complete assembly then back on the boat. I’ll let you know how it goes.

 

[Sea Rider]

So got (2) new 115 slow jets, (1)125 middle slow jet, (3) 60 main jets but main nozzles remains same as are/were non available, right ? We hope the machine shop can pull out the screwed main jet on carb 2 and be able to remove the lower nozzle to clean/polish it out which would be ideal for all 3 carbs to work spotless clean. Were the 3 carb's seats heights found OK ?

Which boat type/length/usual number of passengers on board is the 40 HP powering ? After the carbs are placed back and motor is running strong would suggest going for a motor/transom height optimization and soon after a prop maximization to get the max juice out of that 40.​

Happy Boating

 

[Douglasdzaster]

So got (2) new 115 slow jets, (1)125 middle slow jet, (3) 60 main jets but main nozzles remains same as are/were non available, right ? We hope the machine shop can pull out the screwed main jet on carb 2 and be able to remove the lower nozzle to clean/polish it out which would be ideal for all 3 carbs to work spotless clean. Were the 3 carb's seats heights found OK ?

Which boat type/length/usual number of passengers on board is the 40 HP powering ? After the carbs are placed back and motor is running strong would suggest going for a motor/transom height optimization and soon after a prop maximization to get the max juice out of that 40.​

Happy Boating

The 60 are the slow jets,all new. The #1 and #3 have 115 main jets which I cleaned and polished. The #2 is the screwed main jet I got the new 125 for and nozzles are nla. I looked everywhere. Hopefully he will tell me for sure it can be done without damaging the nozzle or the carburetor. Otherwise I’ll have to clean the heck out of it and hope for the best while looking for a used carburetor. All I’m finding now are sets of all three $600 and up. Also new o rings for top and bottom and new o rings for the drains. One new drain plug because I found a crack in one. Got a screw with nut for the stripped out threads on the bottom carburetor which only had three screws and was the dirtiest.The seats are all the way in. Do I have any tolerance on the 15mm height? Like .02 off on one? Have to take the float off to adjust then measure. But they’re all super close if not right on. Sitting basically level with the carb body. When I turn the carburetors over one opens (goes down a little more than the others). Is this a problem? I came up with a solution that should work for the pm I sent you. I have one new tank not vented (per EPA) and one older that is. The fuel demand valve should work on both I hope. This will get rid off some extra fittings if I install the valve on the main line like it’s supposed to be. Trying to get as far as I can today. Got to work on the house. I mean get ready for a contractor. Lol I’d rather do the fun stuff. I’ll let you know what happens with the carburetor. As always thanks for walking me through.

 

[Douglasdzaster]

The 60 are the slow jets,all new. The #1 and #3 have 115 main jets which I cleaned and polished. The #2 is the screwed main jet I got the new 125 for and nozzles are nla. I looked everywhere. Hopefully he will tell me for sure it can be done without damaging the nozzle or the carburetor. Otherwise I’ll have to clean the heck out of it and hope for the best while looking for a used carburetor. All I’m finding now are sets of all three $600 and up. Also new o rings for top and bottom and new o rings for the drains. One new drain plug because I found a crack in one. Got a screw with nut for the stripped out threads on the bottom carburetor which only had three screws and was the dirtiest.The seats are all the way in. Do I have any tolerance on the 15mm height? Like .02 off on one? Have to take the float off to adjust then measure. But they’re all super close if not right on. Sitting basically level with the carb body. When I turn the carburetors over one opens (goes down a little more than the others). Is this a problem? I came up with a solution that should work for the pm I sent you. I have one new tank not vented (per EPA) and one older that is. The fuel demand valve should work on both I hope. This will get rid off some extra fittings if I install the valve on the main line like it’s supposed to be. Trying to get as far as I can today. Got to work on the house. I mean get ready for a contractor. Lol I’d rather do the fun stuff. I’ll let you know what happens with the carburetor. As always thanks for walking me through.

I’m sorry all that and didn’t answer your question. It’s a 16’ I measured 6’ xtra deep flat bottom. Monarch. It’s got a 3/4” plywood floor and front deck. The motor is set the highest slot on the trim pin. I looked up the actual model once but can’t find it at the moment. The motor is a short shaft set up pretty good. I took it right after changing the fuel line just me one fuel tank and trolling motor on front. Nice hole shot and trimmed most of the boat out of the water. Felt like I was flying. About as fast as I want to go in a Jon boat. Even got on top of some waves and stayed smooth. I can’t wait to see what she’s got with the carburetors cleaned up. I live near two lakes and the Colorado River. I can do any kind of fishing I want with it. Just have to watch the windy days. I’m goin to give these boys a run for their money when racing to the lines on the river. Took me a long time to find this boat. They’re all narrow around here. Except for the $50k rigs that can’t run as shallow as I can. Here’s some pics. She’s a work in progress. Someone painted the motor pretty ugly trying to camouflage it. The price was right too. The motor is worth more than I paid for the whole rig. Looks a little shabby still but everything is sound. No corrosion on the trailer.

 

[Sea Rider]

Are those carbs made by Mikuni or of similar name ? Tohatsu's main nozzles which looks same will probably match Yam's noozles which will be a goal shot from middle field. As a refference will take a pic and post its lenght, diam and number of mini orifices so to compare against yours.

If all 3 floats heights are around the 15 mm mark and sits leveled to the bowl's edges leave them there, should work fine.

So it's a clamp tiller motor with extended tiller, right ? What's the small box with attached hose for ?

Happy Boating​

 

[Douglasdzaster]

Are those carbs made by Mikuni or of similar name ? Tohatsu's main nozzles which looks same will probably match Yam's noozles which will be a goal shot from middle field. As a refference will take a pic and post its lenght, diam and number of mini orifices so to compare against yours.

If all 3 floats heights are around the 15 mm mark and sits leveled to the bowl's edges leave them there, should work fine.

So it's a clamp tiller motor with extended tiller, right ? What's the small box with attached hose for ?

Happy Boating​

Carburetors are Keihin. BCP 6H40A FK08. Wow didn’t realize you could see that from the angle. The box is covering the 10 micron fuel water separator and those are the fuel lines. I covered them with gorilla sleeve. Same stuff we used to protect hydraulic hoses on construction equipment where I worked. It’s cheap, protection from the sun and you won’t get any nicks in the hose. When I got it the thing didn’t have any kind of fuel filter whatsoever. Now it has that and the OEM mounted where it’s supposed to be under the cowling. As far as the tiller this motor has been modified so much I couldn’t tell you how it looked new. I think every time something broke it got rigged some how. The tiller for it looks completely different and controlled more. The throttle cable is the reason for the black tape but it works. Got a piece of stiff wire on the other side for idling. Lol

 

[Douglasdzaster]

Just got back from town with success. The first thread or two are burred but I hit it with some emery cloth and if you’re real careful to start it straight the jet goes right in. I’m glad he got it. I had to work on the nozzle for a while back and forth to get it loose. It’s taking a long soak right now. Probably didn’t get cleaned the last time because of the jet. It’s the worst out of the three. Went completely through #3 today cleaned it some more and double checking everything as I assembled it. New gaskets , everything in its place. It’s a bugger but I got that screw and nut in place and tightened everything up. First one finished! Then I looked down and saw the little rubber plug that goes over the slow jet. Lol So I got to do it twice today but I got one down anyway.

 

[Sea Rider]

Glad to read the jet and nozzle were successfully removed, what solvent are you using to soak the nozzle ? will be a good idea to soak the upper carb part in the same solvent overnight, m/polish the internal nozzle's seat which must be really gunked, before the cleaned and shinny old nozzle is put back in.

With respect to the floats, the small metal rectangle where the needle hangs from is too small to play with and hard to reach, could end breaking the plastic float. Yep,it's a must install the round rubber plug under each nozzle...

Happy Boating​

 

[Douglasdzaster]

Glad to read the jet and nozzle were successfully removed, what solvent are you using to soak the nozzle ? will be a good idea to soak the upper carb part in the same solvent overnight, m/polish the internal nozzle's seat which must be really gunked, before the cleaned and shinny old nozzle is put back in.

With respect to the floats, the small metal rectangle where the needle hangs from is too small to play with and hard to reach, could end breaking the plastic float. Yep,it's a must install the round rubber plug under each nozzle...

Happy Boating​

Using lacquer thinner. Is it ok to soak the nozzle all night as well? Didn’t think about resoaking the carburetor itself. I’ll get it in the bucket tonight as well and tomorrow polish the nozzle seat and nozzle. Thanks for the thinking. Yea when I looked down and saw that rubber plug made me speak in tongue. Lol. I’m setting the pilot screws back to exactly where they were. You think after all this there’s going to need to be some adjustments? Or should it be ready to run? I’m getting closer now. Be ready to pull that cord in a couple days I hope. Keeping my patients though. No more mistakes.

 

[Sea Rider]

Will be much easier to clean the nozzle's seat after a long overnight thinner soak. Plan installing new spark plugs or the old ones are still good to go ? It's impossible to deternine if the carb's mixture screws will need any further adjustment. When reinstalled back to the same position the motor should purr as used to. Does the motor counts with a tach ? Would be ideal to know at which wot rpm the motors runs as usually loaded on flat calm water cond to take all the 40 ponies out of it.

Happy Boating​

 

[Douglasdzaster]

Will be much easier to clean the nozzle's seat after a long overnight thinner soak. Plan installing new spark plugs or the old ones are still good to go ? It's impossible to deternine if the carb's mixture screws will need any further adjustment. When reinstalled back to the same position the motor should purr as used to. Does the motor counts with a tach ? Would be ideal to know at which wot rpm the motors runs as usually loaded on flat calm water cond to take all the 40 ponies out of it.

Happy Boating​

You read my mind about the tach. It doesn’t have one. I was thinking today about prop set up etc. There’s some small devices that are tach as well as temperature sensors. I was wondering how accurate they’d be. Going to investigate. You where right about the nozzle seat. Took me quite awhile to get it cleaned and resurrect the nozzle. I assembled that carburetor today. Now one to go. I found out last night I still had till the end of the month to return the fuel tank and fittings we where discussing the other day. Especially after you said they were known to leak fuel. I haven’t used the tank and most of the fittings. It’s all going back and I’m looking at OEM tanks. Oh, after installing the carburetors on the boat I need to put something on the linkage , springs etc. would silicone spray work. What do you use?

 

[Douglasdzaster]

You read my mind about the tach. It doesn’t have one. I was thinking today about prop set up etc. There’s some small devices that are tach as well as temperature sensors. I was wondering how accurate they’d be. Going to investigate. You where right about the nozzle seat. Took me quite awhile to get it cleaned and resurrect the nozzle. I assembled that carburetor today. Now one to go. I found out last night I still had till the end of the month to return the fuel tank and fittings we where discussing the other day. Especially after you said they were known to leak fuel. I haven’t used the tank and most of the fittings. It’s all going back and I’m looking at OEM tanks. Oh, after installing the carburetors on the boat I need to put something on the linkage , springs etc. would silicone spray work. What do you use?

Oh, and I replaced the plugs not long ago. I’m still going to check them.

 

[Faztbullet]

Here is one of the correct ways to adjust carbs....

Start the engine and place the shift selector in forward gear. Turn the idle mixture screw in clockwise until the engine sputters. Turn it out counterclockwise until the engine begins to miss. Turn it back in until you achieve the highest rpm on your tachometer, which will be a midpoint between the two stumbling screw positions. Adjust each mixture screw in this fashion, achieving the highest rpm on the tachometer gauge.

Step 2​

Locate the idle speed stop screw on the carburetor linkage. You will recognize it by pulling back on the throttle linkage and seeing where a small screw rest against a cam or stop. Look up the idle speed specifications for your outboard in your service manual. It will recommend a maximum idle speed in gear for a warm engine.
Use a screwdriver to turn the idle speed stop screw clockwise to increase the rpm, and counterclockwise to decrease it. Set the rpm to manufacture's specifications, reading that number on the tachometer. Turn the engine off. Remove the tachometer.

 

[Sea Rider]

Gee what a huge collection of wooden cottoned pokers LOL!! excellent to have served the carbs well. With respect to the tach can buy a cheap induction one, would recommend this one : Check Iboats, Amazon https://www.hardlineproducts.com/product/hourtach-meter-up-to-8-cylinders/

It's a day/night boating difference boating with a prop spinning to at least middle to its max factory rpm range as usually loaded. Usually going down in pitch, how much ? only the tach will determine so.

Once the motor has started and after being fully warmed up will know if the carbs are idling good or not, hope so, as the middle carb is running a higher jet number than previous lower one, will probably need to adjust that pilot screw bit less from previous setting. it's just a guess. The pilot's screw only work when the carbs runs at idle/ralenti, once the throttle is opened the carbs runs on the high speed jets and there's nothing to adjust. You could have a motor idling lousy, uneven, but running as a champ at wide open throttle. Are free to follow what's recommended on post 116 or not, it's entirely up to you. Luckily for me only run simple single carbed motors...

The best way of preserving what's under the cowl is to get a middle size bristle brush, spray some shots of WD-40 on the bristles and paint with it whatever needs to be preserved with at least 2 even coats. It's useless to spray a whole can of WD-40 for that purpose as will be collected on the pan. Reapply often or when needed.

Happy Boating​

 

[Douglasdzaster]

Gee what a huge collection of wooden cottoned pokers LOL!! excellent to have served the carbs well. With respect to the tach can buy a cheap induction one, would recommend this one : Check Iboats, Amazon https://www.hardlineproducts.com/product/hourtach-meter-up-to-8-cylinders/

It's a day/night boating difference boating with a prop spinning to at least middle to its max factory rpm range as usually loaded. Usually going down in pitch, how much ? only the tach will determine so.

Once the motor has started and after being fully warmed up will know if the carbs are idling good or not, hope so, as the middle carb is running a higher jet number than previous lower one, will probably need to adjust that pilot screw bit less from previous setting. it's just a guess. The pilot's screw only work when the carbs runs at idle/ralenti, once the throttle is opened the carbs runs on the high speed jets and there's nothing to adjust. You could have a motor idling lousy, uneven, but running as a champ at wide open throttle. Are free to follow what's recommended on post 116 or not, it's entirely up to you. Luckily for me only run simple single carbed motors...

The best way of preserving what's under the cowl is to get a middle size bristle brush, spray some shots of WD-40 on the bristles and paint with it whatever needs to be preserved with at least 2 even coats. It's useless to spray a whole can of WD-40 for that purpose as will be collected on the pan. Reapply often or when needed.

Happy Boating​

I thought I’d check the needle valves by blowing through all three carburetors. The bottom #3 carburetor is quite a bit harder to pass air through than the other two. I remember the float doesn’t drop as far as the other two either. I know I have the float close to 15mm. Can’t remember if it was plus or minus without opening it up. What are your thoughts sir? I know I didn’t have to polish as much on the seat as the other two.

 

[Douglasdzaster]

Here is one of the correct ways to adjust carbs....

Start the engine and place the shift selector in forward gear. Turn the idle mixture screw in clockwise until the engine sputters. Turn it out counterclockwise until the engine begins to miss. Turn it back in until you achieve the highest rpm on your tachometer, which will be a midpoint between the two stumbling screw positions. Adjust each mixture screw in this fashion, achieving the highest rpm on the tachometer gauge.

Step 2​

Locate the idle speed stop screw on the carburetor linkage. You will recognize it by pulling back on the throttle linkage and seeing where a small screw rest against a cam or stop. Look up the idle speed specifications for your outboard in your service manual. It will recommend a maximum idle speed in gear for a warm engine.
Use a screwdriver to turn the idle speed stop screw clockwise to increase the rpm, and counterclockwise to decrease it. Set the rpm to manufacture's specifications, reading that number on the tachometer. Turn the engine off. Remove the tachometer.

Thank you

 

[Douglasdzaster]

I thought I’d check the needle valves by blowing through all three carburetors. The bottom #3 carburetor is quite a bit harder to pass air through than the other two. I remember the float doesn’t drop as far as the other two either. I know I have the float close to 15mm. Can’t remember if it was plus or minus without opening it up. What are your thoughts sir? I know I didn’t have to polish as much on the seat as the other two.

Actually correct that. 2 and 3 are close. #1 opens more and lets air pass through very easy and it’s float is exactly 15mm.