honda 115 efi running problems

[benzico]

hello all, need some help/advice with my engine. the symptoms are, the engine will start and idle smoothly and the revs will increase smoothly using the fast idle lever. upon leaving the pontoon the boat will run good but only for about 5 mins it will then start to miss and starts surging , at this point i have to throttle back and slowly limp back . back at the pontoon the engine runs rough even in neutral and will sometimes stall completely .
Work i have done: cleaned tank, new fuel line tank to engine, new lp fuel filter, cleaned vapour sep tank, replaced screen under hp fuel pump, replaced fuel filter in vapour sep. compression check all @150-160 psi. have tried different tank and bulb. tank vent is not blocked.
At first i thought it could be a fuel issue but now i really do not know, maybe something goes wrong when the engine gets warmer, ht leads/coils ,i dont know , i am starting to get abit down, can anyone shed some light or give me some ideas of what to do next.
Thankyou all.

 

[IGIFF]

Re: honda 115 efi running problems

You need to figure out if it is fuel or electrical.I have once had fuel starvation caused by a blocked vent filter,this is situated on the vent line running up behind the inlet manifold and back down onto a fitting on the midsection.Check that this is clear and the filter not blocked by blowing through it,if air can't get out,fuel can't get in..The other thing to do is to bypass your fuel supply all together by fitting a remote tank hose directly onto the fuel pump with the cowl off and run it and see if this fixes it.If not let me know and we will go further.