hard to get going

[scott68]

1984 johnson 70
ok, have had this problem since i bought the boat 4 years ago. when taking off from slow motor bogs down and wants to die, push the key primer and it clears and goes. rebuilt the carbs twice, switched carb positions, seafoamed, change plugs, tank bulb is always firm, but if i spray premix into the top carb it clears and goes, even after switching carb position. tried all suggested over the last few seasons with no change and just dealt with it. only thing never mentioned was the fuel pump, could this be the problem as it has never been touched since in my care? sorry for the long post

 

[HighTrim]

Re: hard to get going

When you cleaned your carbs it sounds as if you missed the jets, they will need to be removed and thoroughally cleaned.

 

[jtexas]

Re: hard to get going

The fuel pump fills the carb bowls - if you had an empty carb, pushing the primer wouldn't make it go any faster. How long will it idle without dying?

Did you link & sync?

What's the idle RPMs, in neutral and in gear (lower unit submerged)?

Do any of your carbs spit up fuel at idle? (and not just a tiny droplet now & then)

Do you remove the core plugs when you soak the carbs?

It does sound like a classic case of gummed up jets. I'm thinking off-idle jets.

One thing to remember is, if a cylinder is starved for fuel, you're dragging it through a dry hole - not good.

 

[tashasdaddy]

Re: hard to get going

http://forums.iboats.com/showthread.php?t=244013

 

[scott68]

Re: hard to get going

as i said, i did all this, soak , clear jets, new kits each time, except the link and sync, the boat has no tach and was never sure even after reading how to do this but the same result every time, but what i don't understand is why it still does it even tho i switched the top carb with the bottom carb. it idles fine runs at slow speed fine, should say great, it's only when trying to really go, also if i ease it, it will eventually get going, could the top carb bowl not be filling as quickly and hard acceleration?

 

[HighTrim]

Re: hard to get going

but did you physically remove the high speed jet?

 

[jtexas]

Re: hard to get going

Don't feel bad, we always give the new guys a hard time about not being thorough with their carbs.

If you can make it to WOT by easing, or feathering, or babying the throttle, then I'm going to say -- and this is a wild guess here -- your throttle valves are opening before the spark has advanced enough.

Could be because it's starting from too low of an idle speed.

Or because the cam is hitting the roller off the mark.

 

[Pleaselunkers]

Re: hard to get going

I'm new to the forum and know almost nothing about motors, so take the advice for what its worth. I had the same problem you had with the bulb staying hard, and could only keep the engine idling by squeezing the primer bulb. Otherwise it ran for two minutes then died.

I changed my fuel pump tonight and the problem appears to be solved. The advice I got from a board member and also from a website about trouble shooting 9.9hp johnson engines advised me to remove the fuel line end entering the carburator from the fuel pump.

Put a bucket under the fuel line and squeeze the fuel tank bulb. If your fuel line isnt clogged up, (which its doubtful it is), fuel will spurt out very quickly. Now pull the starter rope. If fuel does come out of the line when pulling the rope you do not have a fuel pump problem. Fuel would not come out of the line when I pulled the rope. I replaced it today and fuel would come out. I had it running for 15 minutes without it bogging down or dying.

The fuel pump was 40 dollars on iboats.com and 10 for shipping. It took two days to get to my house, very impressive time for ground shipping when I ordered two days ago at 4pm. I also replaced the fuel line from the fuel pump to the carb with clear line for about 5 dollars with the clamps at a local hardware store. I can be sure now that the carb is getting fuel without taking the line off.

 

[scott68]

Re: hard to get going

when you speak of high speed jet or any jet for that matter, i will assume you are talking about the little brass screw in fittings that are buried in the carb behind other screws, with a hole in the middle of it? then yes, they were removed and soaked with the carbs and blown out with compressed air and checked for clogs. if i have missed something here, let me know