Boat loses power after running WOT for a few hours. Why?

[Scott Danforth]

Re: Boat loses power after running WOT for a few hours. Why?

to see if its vapor lock. leave your hatch cover off, and keep your blower on since your problem comes during cruising.

there is no load on the engine in neutral, so it takes very little fuel to make the engine run to full RPM. in fact a healthy engine will run to full RPM with no load and 5 of the 8 spark plug wires removed.

 

[CaptainMax]

Re: Boat loses power after running WOT for a few hours. Why?

I will try that. Another mechanic that I just got off the phone with told me that when the problem happens, I could take a rag, dip it in my cooler with cold water and ice, drape the rag over the pump for a few minutes and then see if the problem goes away. I'll try all these suggestions next time I have a day on the lake.

In the meantime, how do I install a oil pressure switch in my engine? I have no idea where it goes, how it goes, and what it attaches to. Is there a pre-threaded part of the engine that I just screw an OPS into? Does it go into the oil pan? I am so lost on how to do that. Any help is greatly appreciated. Thanks!

 

[Scott Danforth]

Re: Boat loses power after running WOT for a few hours. Why?

http://forums.iboats.com/showthread.php?t=489129&highlight=oil+pressure+switch+wiring

 

[bruceb58]

Re: Boat loses power after running WOT for a few hours. Why?

http://forums.iboats.com/showthread.php?t=489129&highlight=oil+pressure+switch+wiring

Would be best to find an oil pressure switch that has 3 terminals, NC, NO and common. NO goes to ignition and NC goes to your starter assist solenoid so that the fuel pump operates while cranking. If you just get a two terminal switch(NO and common), you can still have the pump operate while cranking if your starter solenoid has a terminal that is energized only during cranking. Another way with thetwo terminal switch is to use a diode from the shift assist solenoid.

If your alternator has an output(usually L2) that only puts out voltage with the engine running, you can use that instead of an oil pressure switch to drive a relay which then drives the fuel pump.

 

[CaptainMax]

Re: Boat loses power after running WOT for a few hours. Why?

Hello guys! Sorry its been so long since I've last posted...I have been super busy and havent had much time at the lake to work on the boat. Anyway, here is the progress I've made since we last spoke: I have determined that my fuel pump is definitely the issue. I tried the "cold rag over the pump" and it worked! I guess the pump really was vapor-locking to a small degree. Anyway, enough with that crappy electric pump...I ordered an OEM mechanical pump! I'm very excited, but I now have questions on THIS. The part I ordered was the Sierra 18-7267. The pump is made for the "ford 302" which is what I have. Here is my issue: it looks like the fuel lines leading into the pump are on the horizontal, and the fuel lines on the boat run vertical. If I get a 90 degree elbow, will this work? It appears as if the inlets on the pump are 1/4"...does that mean the fuel lines are also 1/4" or are they 3/8"? Furthermore, am I guaranteed that this pump will work for my boat? Any and all help is appreciated, as always. Thank you to you all who have helped me so much in the past!

Max...Captain Max.

 

[Scott Danforth]

Re: Boat loses power after running WOT for a few hours. Why?

the inlets on the pump are 1/4" NPT which is why there is the flare adapter to the 3/8" tube. FYI - the hole in the 1/4" NPT and the 3/8" tube are the same.

as far as teh pump, it sounds like you may have an incorrect pump. normally I would recommend comparing it to the old pump, however you replaced that with the problematic electric pump.