fuel pump and/or power pack?

[83ebbtide]

I have an 83 175 Johnson. Rebuilt carbs to help with a bogging issue. Starts and idles better on muffs but still have a pop out the exhaust. Placed the timing light on the plug wires and it appears to be firing ok. Talked with a mechanic when I bought a new primer bulb and he said the pop could be a power pack firing out of time. Ever heard of this?

The other issue is I cannot get the primer bulb to firm up completely. It acts as if it is pushing fuel past the pump. Checked for leaks in the lines and don't have any. The bulb is new. Can the fuel pump diaghram be weak and letting fuel push past it? I know the primer bulb should firm up completely to where you can't squeeze it any longer but this isn't currently happening.

She's better but not quite there yet. Thanks for all the advice, it has proved extremely valuable.

 

[83ebbtide]

Re: fuel pump and/or power pack?

Anyone have some ideas?

 

[kenmyfam]

Re: fuel pump and/or power pack?

Check the fuel pump output.

 

[83ebbtide]

Re: fuel pump and/or power pack?

My motor has two pumps. You probably already know that. So do I disconnect the fuel line on the output side, pump bulb and see if fuel comes out?

 

[kenmyfam]

Re: fuel pump and/or power pack?

My motor has two pumps. You probably already know that. So do I disconnect the fuel line on the output side, pump bulb and see if fuel comes out?

Disconnect between 2nd pump and carbs, put muffs on to save the impeller and crank for at least 10 seconds into a watched container.
Regular strong spurts = fuel pump O.K.
Strong spurts tapering off as time goes on = failing pump
Trickles or nothing = bad pump or pumps.
Hope this helps.

 

[hawkf250]

Re: fuel pump and/or power pack?

It definately sounds more like a fuel issue to me, I would get an inductive timing light just to make sure that you are getting spark to all cyl. but this wont tell you how strong it is. But with the primer not firming up it sounds more like the bulb its self is faulty or there is air getting in the fuel system ( most likely) try an external fuel tank and a new hose/ primer bulb and see if you can get a firm bulb, if so, your getting air in your onboard system assuming there is one, and need to check all hoses and fittings including the ones on the fuel tank itself. If not, then you need to look at all the hoses on your engine and make sure that they are good and that your not leaking fuel there anywhere. also I would give the carbs a good cleaning too as a clogged jet or stuck float will cause the same symptoms.

 

[83ebbtide]

Re: fuel pump and/or power pack?

Thanks guys. Hawk, I have rebuilt the carbs and fixed what feul leaks I found which did help. I have also replaced the primer bulb with a new one in case there was an issue with it and because of its age.

It starts better than it has in a while but the popping issue has me thinking power pack and the primer bulb issue has me thinking fuel pump. I have had a couple of mechanics mention the power pack firing out of time as well.

Kenmyfam, I will check out the pumps in the manner suggested. May be tomorrow as it is getting dark this evening. Do you have any thoughts on the power pack theory?

 

[kenmyfam]

Re: fuel pump and/or power pack?

Kenmyfam, I will check out the pumps in the manner suggested. May be tomorrow as it is getting dark this evening. Do you have any thoughts on the power pack theory?

Not till the fuel pump status is determined.

 

[83ebbtide]

Re: fuel pump and/or power pack?

Thanks. I'll check tomorrow and post finding.

 

[ondarvr]

Re: fuel pump and/or power pack?

The squeeze bulb shouldn't feel like fuel is leaking out and collapsing when you hold pressure on it. They can be bad even when new, so it could still be an issue, the other cause would be the float needle(s) still leaking.

The squeeze bulb will push fuel through the pumps with ease, this isn't an issue.

 

[83ebbtide]

Re: fuel pump and/or power pack?

The squeeze bulb shouldn't feel like fuel is leaking out and collapsing when you hold pressure on it. They can be bad even when new, so it could still be an issue, the other cause would be the float needle(s) still leaking.

The squeeze bulb will push fuel through the pumps with ease, this isn't an issue.

Thanks for clearing that up. Is there a way to test to see if fuel is getting by them? The old needle and seats looked good so I may put them back in. I used Sierra rebuild kits which some on here have stated they had problems with.

I'll grab another primer bulb as well to see if it makes any difference. They're cheap.

 

[83ebbtide]

Re: fuel pump and/or power pack?

Finally got a chance to take it out to the lake to test and it runs great on the top end but surges or just dies coming out of the hole. Found some trash in the fuel line going to the fuel pump so cleaned it out and still had the same issues. Primer bulb seemed to firm up this time. Acts like it "loads up" at idle and will die if it stays there too long without lifting the warm up lever. Pushing in on the key didn't seem to help any either. Stream coming from fuel pump looked good. I'm thinking of pulling the carbs and checking them again! What else could this be, it's about to beat me and I don't give easily!

 

[83ebbtide]

Re: fuel pump and/or power pack?

Anyone?