2.5 wont go above 5000 rpm's

[stivov1]

hey guys, having an issue, few weeks ago, put new 2.5 powerhead on my boat, stock strong running motor, ran it on the lake for a few days, ran great, turning 6500 rpm, then all of a sudden, started cutting off, was not getting fuel. so came home, removed the primer bulb, removed diaphram pump on motor, installed a 4-7psi electric fuel pump, ran new lines right to carbs, took boat back out and now seems under powered, and wont go above 5000 rpm's, any thoughts? was thinking electrical, stator or something, but was running perfect until fuel issue. appreciate any input!

[eli]

when you say new is it a nic bore ?

[stivov1]

sorry, new to me, 1995 I believe

[eli]

reason i asked is there have been a few blocks coming back from u. s. chrome after getting the nicasil re done run for a few hours then rings are wore out .including 2 of mine

[stivov1]

not this one, stock with great compression, was 130 each cylinder, guess I'll check again to make sure, but any ideas?

[rkmirage]

When you're at wot, 5000, push the primer a few times and see if it picks up. That pump might not be providing enough fuel.

[stivov1]

primer? choke?

[tunnelmike]

Check tank vent. You can only get as much fuel out as air in after the tank has negative pressure. Or pinched line ? Mike

[stivov1]

thanks mike, ok ill double check, I replaced all lines to 3/8 more flow

[rkmirage]

primer? choke?Yeah, the choke, this will shoot in some fuel, if it picks up rpm it's starving for fuel.

[stivov1]

ok I'll try and see