Honda 90 high speed failure

[Skiffman12]

Greetings;
I have a BF90 Honda (unsure of year) which idles smoothly and runs steady up to about 4000 rpm. Recently replaced all four low speed jets and soaked and cleaned the carbs. Appears to be fuel starved and rpm's will surge for brief period if choke is applied and then returns to 4000 rpm. Normally achieves another 1000 rpm on normal day. All four cylinders appear to fire. Normally motor achieves over 5000 rpms and runs steady. Is there an inherent problem with the high speed jets? Suggestions would be appreciated.
Thanks in advance.

 

[Nick on the Bad Habit]

Re: Honda 90 high speed failure

These motors are very fussy about clean fuel. Make sure the fuel filters are new, and try again.

 

[zzzzz]

Re: Honda 90 high speed failure

use a portable tank to run the motor...this will isolate the boat from the motor to tell you where to look...it could be your anti-siphon valve at the top of the fuel pickup tube on the tank...they can get gummed up and stick restricting fuel flow

 

[Skiffman12]

Re: Honda 90 high speed failure

Thanks for the info.
I dumped all the fuel and changed both filters. Haven't run it yet. I will post the results as soon as I test drive it. The in-tank valve will be next.

 

[Nick on the Bad Habit]

Re: Honda 90 high speed failure

Don't forget to check the rubber o-ring at the fuel line connector. The smallest nick can allow air to be sucked up, instead of fuel.
Nick

 

[Spaceman]

Re: Honda 90 high speed failure

You also might try to purge any water that could be in the entire fuel system , include the fuel line, especially where the line loops and water could be at the bottom of the loop. Remember fuel is lighter than water and it could be anywhere the gas sits, tank ,filter, line, or/and carb. bowls.