Hello I have a Yamaha 140 H/P v4 Year of make is 1995 I suppose I`m not sur about it.I bought it recently. It works good on idling , on giving the gear it works good on slow moving, but when increasing the speed, it slows and wont speed up. I inserted a new spark plugs. To say the truth I have the inlet of the fuel D/F filter. is broken, but I am not supposing that there`s a lack of petrol flow, I am supposing that there might be some dirt in the jet, but these were clean before.I even sprayed some calburator cleaner but it did not work out.