Johnson Seahorse 1996 4hp 2-stroke: No tickover

[wizard]

As stated no tickover on starting this year despite the fuel stabiliser run through the engine at the end of last year prior to laying up the engine for the winter. The tick over was variable last year as I remember.

I assume the two strokes are the same as 4 strokes in having a main jet and an idle jet. So my question is that as the most likely cause of the problem is a blocked idle jet has anyone got a exploded diagram of the carb for this engine or a manual that I can take the method from to strip and clean the carb please.

As usual grateful for all help and tips.

 

[Lakesailor]

First stop is a good clean out of the carb. Blow through with an air line if you can. Will it tickover if you use the choke control? That's usually a clue.
It may be an idea to try a new plug as well. For about £5 it's an easy and low cost option and may be the answer.

 

[No Regrets]

Drop the float bowl off, and remove both the pilot and main jets. They will be bronze coloured...fairly obvious once float bowl off...

Clean the holes out with pins, needles, whatever until you see daylight through them. Then reassemble carefully, checking for fuel leaks!!

Airlines can blow carb seals. I wouldn't recommend this unless carb is already taken apart...

 

[BarryH]

Clean the holes out with pins, needles, whatever

.......really! If anything I would be inclined to soak them in carb cleaner and the blow them through, not poke them about with anything!

 

[30boat]

Cleaning air or fuel passages in carburetters with metal objects is unadvisable.The castings are soft and can be easily damaged.Carb cleaner and an airline is much safer.If that doesn't work you can get a drill of the same diameter as the hole and use it by hand to bore through the deposits.They are available online.

 

[VicS]

First stop is a good clean out of the carb. Blow through with an air line if you can. Will it tickover if you use the choke control? That's usually a clue.
It may be an idea to try a new plug as well. For about £5 it's an easy and low cost option and may be the answer.

I agree with LS may well need a proper carb clean. esp if you can get is to run with a bit of choke. I agree dont poke jets with any thing that can damage them. I use soft copper wire when necessary

Well worth trying new plugs. ( Two of them!) Use the recommended Q series Champion plugs, which are inductively suppressed. QL86C I beleive allthough QL77JC4 will also be suitable. Gap should be 0.030"
Avoid resistor plugs such as NGK plugs with an R in the number eg BR7HS although NGK plugs with a Z in the number eg BZ7HS are inductively suppressed and IMHO would be suitable.

You will find parts lists and exploded diagrams here http://epc.brp.com/Index.aspx?lang=E&s1=6548a371-e28d-4aed-a842-afaefab5579f
or http://www.boats.net/parts/search/BRP/JOHNSON/1996/parts.html

Adjustment of the carb at http://forums.iboats.com/engine-fre...sorted-carb-variations-joe-reeves-167352.html

You dont state the model number so cannot point you in exactly the right direction for info specific to your engine

 

[Lakesailor]

2 plugs, yes. I had one of these and still can't get a handle on them making it a twin. Makes it too complex and twins sound like they are racing all the time.

BTW. Don't work on it over the stern of the boat if that is where it is at the moment. At least get it in the cockpit. Little bits have a habit of springing off and falling with a gentle splash.

 

[wizard]

I agree with LS may well need a proper carb clean. esp if you can get is to run with a bit of choke. I agree dont poke jets with any thing that can damage them. I use soft copper wire when necessary

Well worth trying new plugs. ( Two of them!) Use the recommended Q series Champion plugs, which are inductively suppressed. QL86C I beleive allthough QL77JC4 will also be suitable. Gap should be 0.030"
Avoid resistor plugs such as NGK plugs with an R in the number eg BR7HS although NGK plugs with a Z in the number eg BZ7HS are inductively suppressed and IMHO would be suitable.

You will find parts lists and exploded diagrams here http://epc.brp.com/Index.aspx?lang=E&s1=6548a371-e28d-4aed-a842-afaefab5579f
or http://www.boats.net/parts/search/BRP/JOHNSON/1996/parts.html

Adjustment of the carb at http://forums.iboats.com/engine-fre...sorted-carb-variations-joe-reeves-167352.html

You dont state the model number so cannot point you in exactly the right direction for info specific to your engine

Thanks Vic I have tried two new plugs, the resistance ones I had trouble with years ago so am up with that.

The model is BJ4BREDS 1996 SERIAL G 03965020

I need the detail to strip the carb. I never take anything apart till I know what I should be doing (saves money usually). Thanks for all the other replies.

 

[VicS]

Thanks Vic

I need the detail to strip the carb. I never take anything apart till I know what I should be doing (saves money usually). Thanks for all the other replies.

The professionals would suggest doing a compression test before going any further. No spec figures available but generally reckoned that both cylinders should be within 10% of each other.

Checking sparks, eg with something like Lakesailor's improvised spark tester would be a good move too.

you might find some info on stripping and cleaning the carb in http://boatinfo.no/lib/evinrude/manuals/1990-2001johnsonevinrude.html#/0

 

[Lakesailor]

As well as my home-made spark plug tester I also have a set of these which are amazingly good.

The original spark tester - which doesn't require a spark plug

 

[wizard]

Now sorted, I found an exploded diagram on the web for the carb - guess what - no idle jet. It works on the mixture idle screw and the tick over cable control. Now ticking over happily and the best bit is I didnt have to strip the whole thing down and it didnt cost a penny

 

[VicS]

Now sorted, I found an exploded diagram on the web for the carb - guess what - no idle jet. It works on the mixture idle screw and the tick over cable control. Now ticking over happily and the best bit is I didnt have to strip the whole thing down and it didnt cost a penny

Not difficult to find an exploded diagram when I'd given you 2 links to follow!

No jet may be but the passages behind the idle screw mixture can become blocked . In extreme cases it's necessary to remove the plug and the lead shot to access these passages. That is why both items are included in the carb kit