mariner 15 hp model 651s 001978

[MARK BRAY]

Anybody help with what seems to be a minor problem. Once engine starts which does take a few pulls ,needs a lot of choke .then dies.After a short time of stop starting the engine then runs smoothly idles lovely without hitch, for an old engine it runs great. Any comments most welcome... Thanks..

 

[Laddies]

Re: mariner 15 hp model 651s 001978

It sounds lean have you cleaned and adjusted the carb?

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

many thanks for replying,is there an easy way of adjusting the lean running carb ? mark....Also the spark plugs are NGK B7HS ,are they ok? thanks again...

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Plugs are right gapped at .040, on the front of the carb at 12 oclock there should be a adjustment screw open it about 1/4 turn (C/clockwise) and see if that helps.

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Thanks for your advice ,I will give it a try Mark Bray

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

I ADJUSTED THE MIXTURE SCREW ,BUT STILL NO GOOD.THERE IS A DEFINITE PATTERN OF BEHAVIOUR WITH THE ENGINE .WHEN COLD ,PULL CHOKE OUT AND IT FIRES UP 2nd GO .IT THEN IDLES FOR A FEW SECONDS THEN DIES,THE CHOKE NEEDS TO BE LEFT IN THE SAME POSITION TO RESTART AND AGAIN 2nd PULL SHE WILL FIRE. I HAVE CHECKED THE CARB,CLEANED AND CHECKED JETS. THE ONLY PROBLEM WHEN I BOUGHT THE ENGINE WAS A SEIZED CHOKE PLUNGER WHICH I EVENTUALLY FREED,ITS STILL A LITTLE STICKY BUT SEEMS TO WORK OK.AS I SAID BEFORE ONCE YOU GET OVER THIS, SHE RUNS PERFECTLY HAPPY.ANY OTHER IDEAS, IF YOU DONT KNOW NOBODY WILL. THANKS AGAIN FOR YOUR TIME.....MARK ...{across the pond}

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, I know that you don't want to hear this but I am afraid that you missed something in the carb. The reason it starts so well is, thats not a choke on the engine, it's a primer and when used it squirts fuel in the engine but when the only fuel that the engine has is from the carb it fails to run properly.

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Thanks Again For Coming Back To Me So Prompt,the Plunger On The Carb Is Operated By A Linkage Which Goes To A Knob At Front To The Left Of The Stop Button, It Is Marked Choke.the Engine Once Warmed Will Then Run Lovely On Its Own, Have I Interpreted Your Message Incorrectly? Thanks Again Mark

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, if I understand you the engine runs poorly just after start up, so my though was it started well on the primer then relied on fuel from the low speed circuit in the carb which could be a little lean, when the engine warmed up the lean condition went away because the mixture was teetering on the lean side. That could be caused by a dirty carb or a lean mixture setting on the idle screw. Bob

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Bob I Dont Know Whats Happening Now ,but Have Taken Carb Off ,removed Jets ,cleaned Again ,put It Back On .it N0w Runs Fine On Choke .wont Run Normally Now Though ,its Now Reversed To What I Started With .now As You Try And Put It Under Load It Conks Out .ive Adjusted Mixture Screw In Different Positions ,still No Good. Is It Time To Take It To A Dealer Before I Really Muck It Up? I Assume You Mean The Choke Is The Primary Circuit? Sorry For Bothering You , Regards Mark

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, I think that there is a check valve sticking, part of the time in your carb, there is a chance if you want to tear it down one more time and let it soak in lacquer thinner overnight and blow it out again before taking it to a shop. Bob

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Hi Bob ,ive Now Got The Carb Stripped Down ,looking At The I Shop Parts List 15a .i Am Trying To Locate The C

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Hi Bob ,ive Now Got The Carb Stripped Down ,looking At The [i Shop Parts List 15a] .i Am Trying To Locate The Valve Which You Mean.ive Also Noticed Looking At The Diagram I Cant See The Air Jet Low Speed Screw Located Front Of Carb . There Must Be Something Obvious ,i Must Be Looking To Hard ,sorry For Being Such A Pain...mark.

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, give me a serial number when I checked parts manuals I find that they used 3 or 4 differant carbs on the 15

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

The Serial Number On Carb Is 65170. Its Night Over Here Now Bob So If Its The Serial Number On The Engine You Want Apart From 651s Oo1978 I Will Look In The Morning .many Thanks Again ...mark.

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, much to my embarrassment after checking the parts manual I find that I have been giving you advice on the wrong carb, your engine is older than I thought. Your carb starts with a enrichment system not a primer, so if you have a idle that is in need of adjustment the screw is right above the carbs. throat at 12 oclock. If after cleaning it the last time and it seems to flood at idle the plunger on the starboard side of the carb that is the enrichment valve may be leaking by (sticking open a little or the seat on the bottom could be bad) it's more than likely not closing properly. I have never seen one of these carbs so I can't tell you if the idle adjustment needle is out for rich or in, so you will have the turn it to find out. We don't even have a manual for the engine as it is a mid 70s engine. Wish I could be more help on this one but I simply don't know.

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Hi Bob ,many Thanks For Spending So Much Time On This One ,now It Seems To Run Fine On Choke Then You Push The Choke Back In And Try To Put It Into Gear And Then Dies. I Will Have Another Look For The Last Time ,then Off For A Service;;;;;once Again Thanks For Your Time.........mark ... Let You Know The Outcome.

 

[MARK BRAY]

Re: mariner 15 hp model 651s 001978

Bob ,just To Let You Know ,carb Is Back On And Seems To Be Running As It Should Be,the Problem Is I Dont Know What I Have Done To Cure It,anyway Is Least I,m Back On Track Many Thanks Again. Mark..

 

[Laddies]

Re: mariner 15 hp model 651s 001978

Mark, we all learn thing through repetition and when we are having troubles each time we redo a project we learn thing without even knowing we have and we take more care each time we repeat the operation. I am happy that you have resolved the problem and it was a learning experince for us both. Good Luck Bob.