Tohatsu 5hp wont start!

[RIB-Teccie]

Fit like Simon, didnae realise you were a Stoney loon!! I'll have to get in touch next time I bring the Rib up.

[RIB-Teccie]

I think the lack of spark is the first port of call. Also check the carb has all the parts inside, check against a parts list. I had a yammie once missing a rubber plug inside the carb which let heaps of fuel into the bore causing serious flooding. Fuel pump can also do this, but you have checked it.

Lastly, if you end up with a wet plug and a good blue spark, I would look at the condition of the bores, coked in rings from over oiling or a bottom crank seal. A bust crank seal usually gives a red colour on the plug.

A good way to test for a strong spark is to insert a screwdriver into the cap and cable tie the shaft up to an inch from the block, a strong spark will Jump 1-2 cm. if not, it's clearly the first problem to sort out.

[SimonCh]

Right, the woodruff key is fine.

I've ordered a CDI unit, and will let you guys know if this solves the problem.

In other news, I bought an old seagull, stripped, cleaned, painted and rebuilded it. Started ok the third pull today!

[SimonCh]

and the plot thickens....

Changed the CDI unit and it made no difference. I did however, notice that if i hold the spark plug next to a bolt, the spark jumps from the electrode to the bolt, but not across the plug itself. If i reduce the gap to about .025" on the plug, it sparks as you would expect it to at .040". So it appears that I am not getting a strong enough spark. So where do I look first with that? magneto? Coil? HT lead?

Please note, this is the same with the old plug, and the brand new one.

Cheers

Si

[bartiny]

I would do the easy things first, Check earths on the coils, renew the plug leads, check other earths on the block.

HTH.

[RIB-Teccie]

Try the screwdriver trick. Find out how far you can move a screwdriver from the bolt. I also assume the recommended plug is being used?

I've not seen what you are describing happen before. It usually looks ok at the plug, but won't jump a larger gap.

Also maybe try without the plug cap and use a terminal, if bit is a resistor cap, there could be too much resistance.

[bingosucks]

By pass the kill cord i had a dodgy one.. use some ht testers to see if your sparking onto the plug from the coil

[A1an]

Cut your losses, sell it to me for pennies and start afresh.

[Peter_C]

The spark might already be jumping a gap...what is the ohms reading of the spark plug wire? Hopefully it is not open. Throwing parts is not the right way to perform diagnostics. Testing then replacing the bad part is.

[SimonCh]

Can't remember the resistance of the HT lead but it was low.

In fairness, everything seems fine with the engine, so why not replace one component at a time until it works?

[bartiny]

Originally Posted by SimonCh

Can't remember the resistance of the HT lead but it was low.

In fairness, everything seems fine with the engine, so why not replace one component at a time until it works?

To be fair there is a plus side to this approach whatever you replace that was not the problem you then could keep as spare parts, plus you get to know how the engine works.

Good Luck

[SimonCh]

Originally Posted by bartiny

To be fair there is a plus side to this approach whatever you replace that was not the problem you then could keep as spare parts, plus you get to know how the engine works. Good Luck

To hell with that - expensive parts are being returned! I'm a tight jock remember!

[bartiny]

Originally Posted by SimonCh

To hell with that - expensive parts are being returned! I'm a tight jock remember!

, In that case check all the earths first then replace the plug leads before digging any deeper, Just my opinion

[spartacus]

Originally Posted by A1an

Cut your losses, sell it to me for pennies and start afresh.

Form an orderly queue Alan... I want to make Simon an offer he can't refuse!

[Peter_C]

If it were me and I had some spark, I would shut off the fuel, drain the carb, let the cylinder dry out with the plug removed, put the plug back in with less than a .30 gap, and spray some Ether down the carb, then see if it starts. It takes three things to make a motor run, spark at the right time, fuel and compression. Nothing more. Ether has some lube in it and will start a motor far more easily than gas/petrol.

You do have compression right?

[m chappelow]

Think i would now start with removing the flywheel & cleaning up the magnets or make sure that nothing is shorting it out such as a piece of broken magnet or iron filings in between the air gap ,Especially on something unknown secondhand , its not unusual for the flywheel to be taken off at some time & to have been put down on a work bench or floor & get metal filings or old welding dross & the like that get stuck to the magnets .

[spartacus]

Any update Simon?

[SimonCh]

Right Rich, i am thankfully now offshore, at bliss, away from that fekkin thing.... also away from my screaming new born!! dont know which i'm most excited about getting home to see. One that wont work, and one that wont stop!

[spartacus]

Originally Posted by SimonCh

Right Rich, i am thankfully now offshore, at bliss, away from that fekkin thing.... also away from my screaming new born!! dont know which i'm most excited about getting home to see. One that wont work, and one that wont stop!

You pick your times don't you for going offshore, I suppose that's just the way it is. I was going to take the family through for the fireballs, but Simple Minds are playing in Stoney so the place will be hooch'n!

Have a Diet Coke on me at the witch'n hour. Catch up in the New Year for a blast up e coast!

[SimonCh]

Diet coke? I'll tell the jokes mate - I'm all fat!

Hogmanay offshore wasn't too bad. In bed by 9, and a nice meal on the first!

Must make that blast happen this year!