High speed miss on a 3.5 Nissan

[randyjaco]

I have an old Nissan 3.5A which is giving me fits. At any speed above 1/3 throttle it starts to miss. I have changed the plug, cleaned and reset the points, checked the fuel flow, checked for carbon build up, cleaned out the cooling system, etc. I am running this motor at sea level so there shouldn't be an altitude problem. The motor starts easily and runs very well at low speed. <br /><br />I have been working on the carburetor mainly because it seems like it is a fuel flow problem. I have cleaned the carb thoroughly, adjusted the needle height several times and adjusted the float level. I notice in the repair manual that it says that the jet should be a #88. The jet that came with the motor and originally ran well is a #92. Could going to the smaller #88 solve my problem? It seems like it would make it worse, but I am at my wits end on solving the problem. <br /><br />TIA <br /><br />Jake

 

[phatmanmike]

Re: High speed miss on a 3.5 Nissan

sounds as though you need to rebiuld that carb completely..... <br /><br />not too many of us on here have knowledge of tohatsu , i own 3 of them as of now...<br /><br />try emailing elvin at www.internetoutboards.com in tampa , florida...<br />they are the parts distribution center for all of north america and he has any answer you could need

 

[randyjaco]

Re: High speed miss on a 3.5 Nissan

Thanks Mike,<br /><br />I will give Elvin a try. I have rebuilt the carb, although there is not too much to rebuild 8^)<br /><br />Jake

 

[phatmanmike]

Re: High speed miss on a 3.5 Nissan

jake , im back with a new idea, is it possible that you are getting water in the cylinder. i had a small johnson( hehehehe) once that was getting water in the cylinder and would hinder the performance at anything above idle... just a thought

 

[loki]

Re: High speed miss on a 3.5 Nissan

Hi Jake,<br />I have a 2.5 that has a similar problem, will not run up to its previous rpm. Does yours look like its burning rich or lean by looking at the plug?