Johnson 9.9 carb.issues.

[dude11]

Hi fellows,It's been awhile since I ck'ed the forum.But when you need help,,you ask.I have a 9.9 hp.1978 Johnson carb. question.Has anyone ever drilled out the "lead" BB's that block factory drillings? In order to be completely cleaned & rebuilt one would need to do this I would think.If you have,what or where would I find some more for replacement?I've done everything I can think of,but for some reason you can be running fine then it acts like you run out of fuel.I have replaced all fuel lines,prime bulb,new fuel pump,plugs,and what I thought was a carb. rebuild.with new float & complete kit.Kinda at the end of my outboard knowledge list here,so any advice would be very helpful.thax

 

[gm280]

Sounds like you check everything fuel wise except the tank. Is there any possibility that your tank isn't vented properly? That would explain the " it acts like you run out of fuel" statement. You are getting fuel and as it uses that initial amount of fuel, all is fine, until the tank can't draw in any air and that stops the fuel flow and the engine stops. And then air comes in and the cycle starts all over again. Check that first before drilling out any lead balls. However, If you do drill out the lead balls, did you look at common split-shot fishing weights as replacements? IDK, could be a match to work... JMHO!

Another lead ball option. If you know anybody that reloads shotgun shells, they may have different size lead shot and maybe one of those sizes would work as well. Just a thought!

 

[dude11]

Thax for your response gm280,I had a 3 gal.spare tank along for the ride,just to be sure of that.And it did the same thing.I will add that under idling along it never acted up,it's @ full throttle when it happens.No,I didn't think about lead weights,great idea.Prior to drilling'em out,I'll wait a few days for some more of the guy's suggestions.I'll add,that after a failure,I can choke it,and I'm off again.May last 5 min.or 5 sec.or 30 min.there's no rhyme or reason---I'm stumped.

 

[racerone]

Report the results of a compression test.---Has the water pump impeller been looked at / replaced.--Does the spark jump a gap of 3/8" or more ?-----I have worked on many OMC carburetors and have never had to remove those lead shots.--I think the problem is somewhere else.

 

[dude11]

Hi raceone,as compression test,78 top 79 bottom.Yes I replaced impeller.I can't say on spark jump because I snatched the carb.off yesterday after a trip to lake for a test hit.I just knew the fuel line to tank was the problem so I had replaced it with new style hose.But no;so I racked the brain & thought well maybe the float is sticking a bit.because it acts like once the bowl was emtpy she'll fail.Nope new style float & needle working smooth as it should.I just thought that since I didn't remove BB's in the rebuild??Just maybe--like I said I'm stumped If the spark is weak why will it do fine soon as I get it recranked??Btw,,are you saying to pull plug wire & ck fire jump to plug or block??thax

 

[AlTn]

if the needle valve is one that has the rubber tip, it may be hanging in the seat. BRP has gone back to the all metal valves, btw. I worked on a 6 hp. that was causing similar issues to yours and this was the fix for it. I'd follow Racerone's suggestions and agree as well that the lead shot issue is improbable.

 

[racerone]

Checked reed valves ??---Looked into possible issues with crankcase compression ?

 

[dude11]

Wow,,raceone--Your talking maybe over my head,lol.Nope,I wouldn't know how to go about those test.Does it sound like that could be a possible cause?

 

[dude11]

if the needle valve is one that has the rubber tip, it may be hanging in the seat. BRP has gone back to the all metal valves, btw. I worked on a 6 hp. that was causing similar issues to yours and this was the fix for it. I'd follow Racerone's suggestions and agree as well that the lead shot issue is improbable.

Thax for your input.In answer,yes it does have the rubber tipped needle,but like I said,it seems to be working fine.I even replaced the cork float with a new plastic one.There's a ton I don't know about outboards,but I tinker alot with small engines & have crossed many tro.I can deal with.But this problem has me scratching my head.lo l My fishing world hasn't ended as I also have a 6 hp.johnson for a backup.

 

[racerone]

Describe in some detail what your motor is doing / not doing.----If it seems to run out of fuel what happens when you operate the manual pump ?

 

[dude11]

Describe in some detail what your motor is doing / not doing.----If it seems to run out of fuel what happens when you operate the manual pump ?

When it starts to fail,I can grab the pump & work it but it'll die before I can hit it over a few licks.I've tried pulling the manual choke,,it sometimes seems to help,but there again it'll die.Now this thing idles perfect,cranks within couple pulls(cold start) If hot cranks on half pull.It screams @ WOT 21 mph.on a loaded 14 ft.jon with two people.But all of a sudden it'll die like you ran empty,choke it pull it a couple times,bam,your off & running again.Go figure??

 

[racerone]

A simple answer is required.-----Does spark jump an actual gap of 3/8" or more, yes or no.

 

[dude11]

A simple answer is required.-----Does spark jump an actual gap of 3/8" or more, yes or no.

I can't really answer that right now,I removed the carb.to ck float.To get it right,should I have it running & pull plug wire and see 3/8" fire to the plug or to the block??I will replace carb.& ck if you think that be be the cause.If I had to point at anything a little off,is the throttle response is a little off in my opinion.But not all motors run exactly the same.Not sure if that matters.thax so far for your help.

 

[Will Bark]

No, you should get an $8.00 spark tester from auto parts store to do the checking. But I had the same problem as you do on my 77 15 Rude. What I did was adjust the float so that it went to the bottom of the bowl and the fuel pump would keep up with the need for fuel at WOT may be the wrong fix but it works and I ain't going to try to "fix" it anymore now that it is working. Good luck

 

[dude11]

No, you should get an $8.00 spark tester from auto parts store to do the checking. But I had the same problem as you do on my 77 15 Rude. What I did was adjust the float so that it went to the bottom of the bowl and the fuel pump would keep up with the need for fuel at WOT may be the wrong fix but it works and I ain't going to try to "fix" it anymore now that it is working. Good luck

Hi Will,welcome to the madness.lolYou need to see this,I just found it after reading your idea.Now that sounds like a dog that''ll hunt...
This float has 2 adjustable settings, one with the carburetor turned upside down, so the float closes the needle, the bottom of the float should be parallel with the metal body. This is the shut off level utilizing the float needle valve so the carburetor does not flood.

The other setting a drop setting, is how far open it goes, allowing fuel into the bowl. There is a tab on far rear of the float pivot metal. This tab bears against the needle valve seat base. It is the stop for allowing fuel into the carburetor. I have not seen any measurements in any service manuals, but by bending this tab so when the carburetor is laying upright, you can adjust this open height setting. I have found on most of my carburetors 1 1/4" is the setting (longest point from the metal body to of the bottom of the float) that works for me, however an other mechanic found in print somewhere saying 1 3/8" drop. Now to confuse things, just measure the depth of your float bowl. I get .900, or just over 7/8", so anything over that .900" will be meaningless as the float can not travel over the depth of the bowl.

 

[Will Bark]

Sure it can't go any further but I guess it's letting more fuel in before shutoff time and that's enough to feed engine. All I know is that it works for me.

 

[dude11]

Like I said,,you may have the ticket !! As they always say,If it works......Thank you for the reply & info.