repair motor boat

Dear friend, I am Gilberto Ortega of Chihuahua and I have gone buy parts in your shop, I have a motorboat to Mercury Optimax 135hp Nitro 1999 and work starts but after about a minute to stop and start again battle but not achievement working more of 2 minutes. Now I clean injectors in El Paso Fuel Inyectors and put news spark plugs and filter change, but I still problems. once asked you and say me that 90 dollars by diagnostic and that if I accepted the $ 90 is condoned if you aceppted paid the price of the repair. believes that these days could bring my boat to review your workshop? follow the same conditions? Do you Think that you can help me about that?