idle problems

[markbitters]

20hp mercury 2oo does not idle and dies when put into gear

 

[milehighboater]

Re: idle problems

How old? Has there been any work done to it that you know of? how well does it start? What fuel mixture are you using? Bit more info is needed.

 

[markbitters]

Re: idle problems

its a 1977 and i just bought to boat last week from a 90 year old guy so i dont know whats been done. im using 50:1 fuel, its cranks for about 10 seconds and fires but shuts off right away and when it does run it stalls when put into gear or when idles down. im thinking its a fuel problem but not sure if there are any common problems that these have.

 

[milehighboater]

Re: idle problems

Most commonly with an older boat the carbs need to be rebuilt. Sometimes though you can just take them off and spray some sea foam in them to clean them out. Just make sure to but the cables back on in the same position as you took them off. The 50:1 fuel sounds right. The good thing though is carb rebuild kits are often preatty cheap and easy to do. For now just do some cleaning and see if it helps.

 

[markbitters]

Re: idle problems

i removed the carb and cleaned out well and, checked spark and put a new set of plugs in and ran and adjusted the idle mixture and got to idle good, installed clear line and ran, runs good till it looses its prime and can not see any fuel flowing through the line, is this most likely a fuel pump problem?

 

[Mi duckdown]

Re: idle problems

Yes. Get a complete carb, fuel pump kit, From a Merc dealer. You need to Have your serial number with you. Look at your carb, and ask to look at the computer screen at the dealer to make sure it looks the same. there are some in the same years that are a little different. It is all gaskets and a diaphram. What does'nt come with the kit is the gasket from the carb to the head. buy that also. About 30 bucks all together. Oh yeah don't forget to buy an impeller. 25 bucks. when you have the carb apart run some large fishing line thru all passages and orifices to make sure they are clear.
Check your tank and bulb to make sure they are not the problem. Just pump the bulb when disconnected from the motor to see if it holds pressure.

 

[markbitters]

Re: idle problems

whats the reasoning for buying an impellar?

 

[Mi duckdown]

Re: idle problems

Just because you don't know the history with the motor. and it is good insurance. when motors sit idle the impellars go bad. Do you know when the last time the impellar was changed???

 

[markbitters]

Re: idle problems

when it does run its pumping good water out the pee hole at idle

 

[Mi duckdown]

Re: idle problems

Just trying to save you problems down the road. Do what you want.

 

[milehighboater]

Re: idle problems

Good work on the carbs, with no fuel coming through check the check valve in the bulb. mine was stuck closed I had to take it off and clean it too. Now it works fine. I'm sure you will need some parts but no reason to replace something that is working just fine. The impeller is one of those "just in case" parts. They are fairly cheap and keep the engine from over heating. as for me we have small lakes I am running a 10 yr old one and it works just fine. Up to you though.

 

[markbitters]

Re: idle problems

i installed a new bulb last week, it had the factoy 1 on and was leaking at the crimped fitting.

 

[milehighboater]

Re: idle problems

Air getting into the fuel line can cause pressure loss and rough idle.