tohatsu still overheating?

[slimtim]

Following on from my thread about my cooling tell tail...

Tell tail is now fine and has been for a while and engine seems to run ok (although it always needs revs to get her started, and sometimes struggles slightly at idle). However, when I flushed it out last night, the tell tail was quite hot, as was the block...hotter than I think it should be.

I checked the theromstat a couple of weeks ago and it was fine and I will check it again soon, but if that is not the problem, what else could be causing the engine to get too warm?

Why does it always need some revs to get her going (even if the engine is warm) and why does it sometimes (only very occasionally) konk out at idle?

Thanks in advance...

[DM]

Sounds like the mixture's too lean. Try tweaking the mixture screw(s) a 1/4 of a turn.

DM

[slimtim]

ah, interesting you mention that...I had a tweak of the screws but didn't really know what I was doing! I did suspect the mixture might be to lean but would that make it overheat?

Another question (and one I seem to have trouble finding an answer to) when I screw the screws OUT am I increasing the amount of fuel or decreasing it?

My local mechanic has told me I need to screw them right in, then out by 1.5 turns, then out 1/4 turn each until I get the best "pick up" on the throttle...trouble is I couldn't really hear any change!

Also, what should me spark plugs look like? Mine have a matt black coating, but nothing too bad...is this right or should they be cleaner? I suspect this might point to a too lean mixture?

Thanks

Tim

[fast fred]

turn them in lightly till thay stop, turn out 1 1/4 turns, to 1 1/2 turns,
this will only fatten up the lowspeed circuit, but will help idle .this is not easy to do, look for a smooth idle.

to start, you need to crack the timin. when you hit the throttle Timin moves first, then the carbs come in.

brown, brown is the color you want to see. if you are lookin for a burn check
off the plugs, you can't get any thing from them if you've pulled back to the dock. you have to get the motor in the range you are checkin and pull the kill,
with out lettin off the juice. and check them on the spot.

[Hightower]

Dark, sooty spark plugs seem to indicate a rich mixure already Tim. I would check out the cooling again and then get a tune up.

Incidently has your engine got an alarm for an overheating cooling system, if so is it sounding?

[codprawn]

Don't worry about needing some throttle to start the engine - most do!!! I would also agree black plugs mean too rich or not a hot enough spark.

[ADS]

Originally Posted by codprawn

Don't worry about needing some throttle to start the engine - most do!!! I would also agree black plugs mean too rich or not a hot enough spark.

Cold start just choke for my 70HP Tohatsu, you can blip the throttle but it doesn't really need it.

[slimtim]

ok thanks guys. Andy, I think there is an alarm, but nothing sounds.

Can anyone tell me which way I need to screw the screws to decrease the amount of fuel in the mixture? I'm guessing by fast fred's post (thanks) that I screw out to increase fuel, so I may have them too far out at the moment. Fast fred, what do you mean by the timing and how do I go about making sure its ok?

Cheers

Tim

[fast fred]

in for less out for more.when the throttel cable moves, think that one pulls,
on some Carbs crack open, next thing that needs to happen , full timeing needs to kick in, by full i mean what ever factory says for that motor, 20-22deg max, usally done with a low spot on the trottle cam.
if you havent messed with it it's prob ok.

[Scary Des]

Tim if you aren’t sure where the carb screws are it is probably best to start again, screw them fully in and do as your local mechanic suggests. With a bit of playing you will begin to get a feel for what is right andyou are unlikely to do any damage.

With regard over heating, engines do get hot but it is quite difficult to gauge how hot, I would suggest getting a multi meter with a temp probe so you can get a better feel for how hot your engine is. I have one you could borrow if you fancy a trip up the Beaulieu Des