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97 challenger 1800 carb cleaning 101

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cjb

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Well after a week of frustration rebuilding one set of carbs on my boat I now have them ready for the water. Here is what I learn about them.

1997 Challenger 1800

If you have a shop manual, you can rip out half of the chapter that covers carb cleaning and testing. The carb the manual refers to is not the carb that we have on our boats at least not the MAG carb.

For starters our MAG side carb whish has the fuel pump on it has a total of four nipples or plugs for fuel lines. The one on the book has only three of them Pulse, Fuel In and Fuel out. Our carbs have Pulse, Fuel In and 2 Fuel Out nipples and to make matters worst one of the fuel out nipples is marked as and inlet on the pump cover. This might be old news to a veteran but I was new at it. Therefore, when testing for leaks or pop off you will need to cover both fuel outlets and connect the gauge on the inlet whish is on the other side of the pump. See pic.

Fuel Pump Check Valve. These ones are a B… to install. I was told if they look good don’t even touch them. Look for damage on the clear plastic disk and that it mounts flush with the pump body. If it looks god let it bee.

When appalling pressure to the carb for testing make sure all screws are tight. I made the mistake of not having the pump side of the carb tight enough and when I started pumping air in it blew out the pump Diaphragm. After it happened, the Diaphragm had a mark on of the sides so I deiced to change it. These things come in a set so I had to by another set from a Seadoo dealer here $57 just to get a new Diaphragm. Fortunately, I still have to do the other engine so I will use the rest of the kit.

The rebuild kit I got came with new Stainless Hex Cap Screws to replace the original slotted screws that strip all the time. I highly recommend it.

Get a pop off gauge.
 

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Keep your manual intact!.....

Well after a week of frustration rebuilding one set of carbs on my boat I now have them ready for the water. Here is what I learn about them.

1997 Challenger 1800

If you have a shop manual, you can rip out half of the chapter that covers carb cleaning and testing. The carb the manual refers to is not the carb that we have on our boats at least not the MAG carb.

For starters our MAG side carb whish has the fuel pump on it has a total of four nipples or plugs for fuel lines. The one on the book has only three of them Pulse, Fuel In and Fuel out. Our carbs have Pulse, Fuel In and 2 Fuel Out nipples and to make matters worst one of the fuel out nipples is marked as and inlet on the pump cover. This might be old news to a veteran but I was new at it. Therefore, when testing for leaks or pop off you will need to cover both fuel outlets and connect the gauge on the inlet whish is on the other side of the pump. See pic.

Fuel Pump Check Valve. These ones are a B… to install. I was told if they look good don’t even touch them. Look for damage on the clear plastic disk and that it mounts flush with the pump body. If it looks god let it bee.

When appalling pressure to the carb for testing make sure all screws are tight. I made the mistake of not having the pump side of the carb tight enough and when I started pumping air in it blew out the pump Diaphragm. After it happened, the Diaphragm had a mark on of the sides so I deiced to change it. These things come in a set so I had to by another set from a Seadoo dealer here $57 just to get a new Diaphragm. Fortunately, I still have to do the other engine so I will use the rest of the kit.

The rebuild kit I got came with new Stainless Hex Cap Screws to replace the original slotted screws that strip all the time. I highly recommend it.

Get a pop off gauge.



Do not rip out any pages of your manual.....of course the carbs are different. They so state this. You have a MAG carb and a PTO carb. I did notice in your pix, you still have the nipples listed incorrectly.

The MAG carb, in your application has the fuel pump attached to the MAG carb. Some skis and boats do not have the fuel pump attached to the carbs at all. They are attached to a metal plate that is bolted on to the magneto.

In your pix, you have two "outlets". There is only one outlet and it's not a true outlet. The MAG carb is designed to supply fuel to the PTO carb, therefore, you have a crossover nipple that supplies that carb with fuel pressure. The other nipple you list as an outlet is not. It's the recirculation line. The fuel circuit is designed to circulate fuel in a circle from the fuel pump back to the fuel tank.

The pulse line is connected to a reciprocating type pump, that pulsates in and out with the stroke of the engine. There are two check valves that open and close in rhythm to that movement. When the fuel begins to move through the pump, there is an "outlet" (fuel return line) connection that has a restriction designed into the body of the carb, to create positive pressure to each carb. Without it, you would have no pressure to operate the carbs. It also helps keep air from entering your system. The check valves of the fuel pump should be replaced if at all possible. They are easy to do with a little practice. You will need a little soapy water (I use Dawn) and a tooth pick. Once you are ready, put that little button up to the hole and use your tooth pick to help start the edge of the rubber button in. With pressure applied with your finger, it will pop in when you manipulate it about half way around.

Once the fuel circuit has been established, there is a crossover line (only on the MAG carb) that supplies the PTO carb. Both carbs are equipped with a return line that sends excess fuel back to the fuel tank. Some configurations have a "t" set-up in the MAG carb that uses a single return line. But, most that I have seen, come together with a "Y" fitting below the PTO carb and return to the tank.

Motors with the twin carb applications have two different carbs and it is stated in the manual and in the parts index, with different part numbers.

So, please, understand this when you look over your carbs for repairs. Although some parts will interchange, for the novice or beginner, it's best to keep the two carbs seperated.

As for the pop off tester.....there is a sticky in the forum where you can learn how to build your own, using standard plumbing parts from Lowe's or Home Depot. You do not have to blow a bunch of money on something you might only use once or twice a year or less..........you can make due. But building the pop off tester like Nswillin put together, you can also adapt it for pressure testing your engine or jet pump...............:cheers:
 
1. I specified the thread was for the c1800.

2. How are does two not outlets. Do they flow gas out or not. Yes, one is the return and the other is the supply to the PTO carb so they are both outlets. You are just getting technical on me but they are outlets as they flow gas out.

3. The book shows pic and description from a single carb set up. That is why is not correct and can generate confusion regarding fuel inlets and outlets or whatever you want to call them. Something else the book is wrong, it tells you to check pop off pressure on the pump side carb by attaching the tester to the inlet nipple. Lol. Good luck with that.

4. Regarding the pop off tester. So is not ok to spend $50 on a tool but is ok to spend double that on a premium subscription to this website to get answers or books that are available for free some place else.

5. You can go ahead and ban me now.
 
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Got ur back

I agree with almost everything Karl says about the carbs, except this one question.
I know there is a difference b/n the Mag and PTO, but their differences are only the bolt on parts, (eg. accel pump, fuel pump, trottle cable attach...), looking at seadoo source for parts for the carbs, they list them as being the same carbs just different accessories???
Correct me if I am wrong.

BTW sorry for bringing up a horrible post, but I had to point that out.
 
Really your getting upset because someone is telling you to save money. First of all it looks like to me seadoosnipe took his time to try and help you out. I dont think at all he took 10minutes to write a reply to make himself look better then you in anyway. This website is not for cjb its a forum to help everyone out with similar problems. If you are offended because someone answered your question and also probably someone elses for future reference then yes go and delete your own profile. Go and spend whatever it is that you want, if someone on this site tells you to not waste your money it is because I dont know of anyone that uses this site that wouldnt like an extra $20 in their wallet especially when you can use that for gas money. If you dont understand your carbs, or manuels that use pictures as a reference for general use then maybe you need to go and pay someone else to work on your engine since saving $50 is so overrated. I was reading through this post and never felt like anyone was trying to offend you or make you look wrong. I think people actually were trying to help out and out of your own frustration and bad direction follower now your taking it personal. Anyways just trying to keep it real here
 
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