Poorly mota

[TheOrs]

Had identical problem with my Merc 75. The fix was a new fuel line inc bulb & clip (engine end).

Not saying this is what's wrong with yours but they're cheap so probably a good place to start.

[scottyboy]

Originally posted by The Docta
Hi All

Wondered if anyone might have any ideas why my motor is not performing as it should. Its a late 80's 200 hp v6 merc (carb). Just been serviced with new plugs and leads.

Compression check was fine on all cylinders but the motor is not running right. It ticks over fine in neutral and throttle response is very good also sounds fine when given plenty of gas in neutral.

In gear, however, throttle response is poor and it sounds rough when running at low revs / speeds (almost like its missing). Only reaching about 45 - 50 at WOT where as we are used to more like 55-60+ and it sounds like its not reving as high as it should (guage knackered so cant be precise).

Also boat stalled totally when running at flat out yesteday but then started up without any probs??.

I thought it could be fuel related and was gonna replace filter. We normally run 45:1 mix with quicksilver oil.

Any ideas or suggestions would be more than appreciated.

Cheers all - the doc

ps attached a pic of the poorly mota in question

That looks like a 2.4 200 clamshell model? First thing i would do is strip and clean carbs! Sounds like your problem to me! If the engine cuts out after the engine has been held at full throttle for a period of time it normally points at stuck floats! A decent service would include a carb clean anyway!

[The Docta]

Hi All and thanks for all the advice

Hi Scottyboy - spot on mate. Late 80's clamshell 2.4 200. Cracking mota when its running sweet. It wails like a banshee!!

The mota was serviced by fairweather marine in Fareham. The service schedule with them states carb tune but does not mention cleanup.

Is this something that I could do myself or should we take it back to them and ask them to do it??

Cheers - The doc

[The Docta]

Hi All

Took cover off carbs this evening and pumped primer bulb whils engine not running to check for carb flooding. All seemed fine.

When she was fired up, however, we noticed that a fine mist of fuel was being spat out of the barrel of the bottom right carb. This was not noticible on any of the other carbs.

Does this suggest blockage in the right hand side of the bottom carb?? or float stuck open in fuel bowl??

Upon inspection, fuel line, primer bulb and tank breather all seemed fine!

Spoke to outboard mchanic at fairweather and he said £100+vat to strip down and clean the carbs. Does this sound reasonable.

Any thoughts or advice realy appreciated

Cheers all the doc

[michaelcaine]

Spoke to outboard mchanic at fairweather and he said £100+vat to strip down and clean the carbs. Does this sound reasonable.

no it doesnt!

[Cyco]

£100 to strip and clean the carbs on a V6 does not sound unresonable to me, its around 3 hours works to do it properly.


I would however question why they need doing again if it states that they were done in the service report, and ask what does it mean by setting up the carbs?

The only set up that is required is checking the butterflies are fully open at WOT and that the throttle arm returns to its stop on tick over.

[Jon Fuller]

Originally posted by The Docta
When she was fired up, however, we noticed that a fine mist of fuel was being spat out of the barrel of the bottom right carb. This was not noticible on any of the other carbs.

I would be looking into distorted, damaged, or missing reeds if I saw that, on just one carb.

[The Docta]

Hi John and thanks

Could an issue with the reeds cause the problem we are encountering i.e. not getting full revs / power and running rough at low revs whilst in gear but fine in neutral??

Mota is also very slow to pick up when in gear.

Cheers

[Jon Fuller]

It certainly wouldn't help.

I'd start with a pukka spark tester too, as seeing a spark at the 90 thou' permagap plug don't really mean jack shit, it aught'a be able to jump at least 1 inch in open air, then you know it aint breeaking down under compression. then move onto the carbs etc, once you know you have a spark capable of lighting it.

[BluFin]

[BluFin]

[The Docta]

Cheers Blufin - Cheers Jon

Most appreciated