Help please ! annoying cough or Miss !

[Chaney101]

hey there guys, trying to prepare for my striper trip in two weeks. I was running my 2003 2 stroke 90 hp on muffs today. I noticed I could not get my rpms to idle down to 675. The lowest is about 800-850. Anyway, at about 2900-3200 rpm I am getting a horrible miss or cough every couple of seconds. I noticed when it happens a puff of smoke exits a tube coming from the fuel pump to the intake. I put a new zip tie on it and it still does it. I noticed that is where my oil is coming from in the cowling. Any input would be wonderful. Thanks guys.

also the primer bulb will not get stiff?

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

Has fresh gas and SeaFoam.

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

Chaney,
I don't believe it to be wise to run at those RPMs on muffs. And you really can't set a good idle on the muffs, needs to be in the water. Try it on the water and if the bulb still won't stay firm may be time for a fuel pump rebuild.
Others will be along with more advice.

 

[Silvertip]

A primer bulb will not stay firm once the engine is started. Fuel is being drawn through it so it merely a wide spot in the fuel line at that point. It should not be sucked flat however.

 

[studlymandingo]

Don't run the RPMs up while on muffs. You need the backpressure on the exhaust. If you must run the RPMs up with the boat out of the water, then you need a test tank.

 

[w2much]

I am having the exact symptoms as you and look forward to any suggestions. Be more specific on your bulb description. Mine does not get hard when first priming the to start, I can just keep pumping but fuel does not come out of the carb barrels. It starts and runs fine. The bulb is of no importance when the engine is running as long as the hose connections do not leak.

 

[Chaney101]

Same thing here, It will not get firm before I start. Any input on the cough? When it coughs it puffs a white cloud.

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

Have you tried priming the bulb once it gets started? Does that keep it running?

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

it does not stall, Its hard to get to stay running until in warms up. once it warm it seems to be ok unless I throttle back to quick after a long run, then it quits on me.

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

Have you cleaned the carbs?

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

no I have not, does that involve tearing them off and rebuilding? The dang on thing only has about 8-10 hours on it

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

It may not be the carbs Chaney, I was just asking if it was done.

What is your starting proceedure?

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

I try to get the bulb firm first, Then I push to choke and start her up. Most of the time I have to start it with the throttle forward with prop disengaged.

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

If the bulb never gets hard before starting, my guess would be either a bad bulb, leaking fuel line or the fuel pump diaphram.

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

You can also try a decarb. See the FAQ's located on the top of this forum on how to do it

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

I have not cleaned the carbs. Is it tough to do?

 

[Plainsman]

Re: Help please ! annoying cough or Miss !

I would try the decarb first. By the way, do you hear your choke engaging? Maybe a clicking sound,

 

[gss036]

Re: Help please ! annoying cough or Miss !

Sounds like maybe you have a bad diaphram in the fuel pump if you are getting enough back pressure to cause exhaust (*smoke) coming out the hose. If you are not pumping gas through the carbs then it is going into the block via the fuel pump. Cheap easy fix.

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

I pulled the plugs. It looks like they might be running a little rich. I am not sure if they ever retuned it after break in. Would this be anything to be concerned about?

 

[Chaney101]

Re: Help please ! annoying cough or Miss !

I replaced the diaphram. Same problem, bulb still not stiff.