rebuilt fuel pump, cant prime system

[jlabrunda]

motor is 2000 70 hp. VRO disconnected. Fuel pick-up was replaced by me. Cleaned tank of debris. Rebuilt fuel pump. Emptied carb. bowls, did not remove carbs. Replaced missing fuel line clamps and bad looking sections of fuel line, all same inner diameter. Primed system with ball and started engine, ran great! next morning, went to dock, primed ball till hard, no start. removed engine cover for inspection, in-line filter is halve way full with hard primer ball. Removed out going line from pump, primed, gas no problem. Connected line, cant prime. Removed manifold line, primed, connected ,cant. also same when carb. bowl drains removed. Primer ball gets hard but wont fill system. Any suggestions?

[Solarman]

Sounds like carbs and needle valves are blocked up. What was in the fuel tank that made you clean it out

You should replace any other old fuel lines left, if breaking down (ethanol fuel), open up carbs, one at a time (record idle mixture screw setting before removal on each carb. Then remove needle valve and seat, high speed jet, idle mixture screw. Using compressed air with a good nozzle, blow out, all air & fuel pas-sages thoroughly (can use paper towels wrapped around can to catch any debris (for identification). If fuel and oil sat up in carbs for extended time, then carbs must be soaked in carb cleaner for couple hours first. Do not remove linkages or other parts for soaking (can remove choke solenoid if electric).

If any other electric throttle position sensor try to position carb to keep out of soaking solution (some motors require special tools to adjust?). Not sure on your motor?

If you can identify debris in carbs, it may tell you what is breaking down causing problems?

When adjusting float height (must be done anytime seat is removed), needle valve must shut off fuel when float is level (hold carb level, and blow through fuel line, while lifting float till can't blow. If under level carb will starve, if over level fuel will run out of carb throat, and flood cylinder. It must be level.).

Good luck, post back when able if you find anything.

[jlabrunda]

found one issue for no prime.

While going through switch panel, replacing bad looking terminals. I hooked up kill switch wrong. This kept the primer valve/choke energized not allowing system to prime,Motor now runs, couple of primer ball pumps and boom, she starts. Put motor in water, engine runs only up to 1700 r.p.m.s any more and primer ball is pumped to keep running. I have replace all line clamps and replaced missing ones at carb.s. Is there a value that you know of for fuel pump vaccum pressure?

[DorkyDan]

Fuel Pump Problems

I had a similar problem with my fuel pumps. I put in a kit, but it still
would not pass fuel with prime.

Result: I ordered a completely new fuel pump. Turned out the culprit (in my case at least) was a stuck check valve. Most kits do NOT include them. In the process I discovered there are two types of check valves used. The older pumps use a brass "reed" valve. Newer ones have a rubber "Poppet" style valve.

It ALSO turns out ... the actual CAUSE of the problem: Ethanol in the gas. This is alcohol. Alcohol attracts water. Water DESTROYS metal parts. Thus in the newer pumps they've done away with metal valves and gone to rubber. Necessary because of the 10% ethanol in gasoline today.

(Just my input)