Outboard problems

[mainshiptom]

My outboard Tohatsu 70 is playing up ? Revs not very high, maybe not firing on all cylinders?

What shall I check for?

I put in new spark plugs? can I adjust timing?

Tom

 

[ballena]

What do the plus look like after it has been running, do they look the same or is one fouling with oil? if this is the case then you have a weak spark on that cylinder, probably a coils or lead breaking down. The coil and lead assembly is replaces as one piece, your dealer should be able to test it on the bench.

I would not adjust the timing as it is unlikely to have moved unless you have dismantled the throttle linkage. Not familiar with this outboard, but spent years keeping old Evinrudes running sweetly.

 

[mainshiptom]

Thanks, I will check !

Tom

 

[cliff]

First did you check the plug gap on the new plugs?
next are the plug leads on the correct plugs (assumming a 4 cylinder engine).

Next start the engine and rev it up as far as she will go (until mis firing is noted) then pull each plug lead off and replace in turn. Note which makes little or no difference to the running of the engine. If all cyinders are "misfiring" I would suspect hi speed running jet in carb if single carb or if twin carb if the "misfire" is related to cylinders fed by one of the carbs.

As for altering the timeing certainly you can but i wouldn't unless you have already been tinkering with it. Timing should not move on its own
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[mainshiptom]

Cliff

It is a 3 cylinder engine with a fuel injection ! It just will not rev to high revs , and I do think it is somthing to do with either fuel starvation ? or electrical problem?

I will check the plugs again since it is the only thin sericable on this engine apart from changing filters on oil and fuel.

Tom

 

[cliff]

[ QUOTE ]
Cliff

It is a 3 cylinder engine with a fuel injection ! It just will not rev to high revs , and I do think it is somthing to do with either fuel starvation ? or electrical problem?

I will check the plugs again since it is the only thin sericable on this engine apart from changing filters on oil and fuel.

Tom

[/ QUOTE ] Duh! ooops!
Got me there.
O.K. we can eliminate carb problems - no carbs, now starting again - plugs - correct plugs and correctly gapped?
Plug leads in good condition?
Are there seperate coils on this engine?
Is the problem a general refusal to rev or is it a misfire? ie all misfiring or one cylinder misfiring?
This probably is a silly question but I must ask - have you tried to rev teh engine in gear? The reason I ask is I had a 25hp years ago that had an "interlock" that prevented opening the throttle much when the engine was in neutral - I forgot about it one season and spent days trying to figure out why the engine would not come to full revs.

Fuel starvation - blocked filter, "old fuel"?

Can you start the engine somewhere really dark like pitch dark and look for arcing around the coils/ignition leads?

Is the "Choke" jambed out / closed?

Failing the above I am at a loss without actually seeing the engine and I am hesitant to even think about an injector pump problem as those can be costly.

Failing any other advice from the forum, I would call a number of outboard repair centers, describe the problem and see if you can get some free advice as to what the probable cause could be.
Is there no information in the engine manual?

Just been looking at the Tohatsu site at the TDLI 70.
If that is your engine I would take it to the Tohatsu dealer for repair - too many electronics etc.
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[chippie]

iboats .com has a forum with loads of expertise on outboards.