67 60hp fuel issue?

[Lion hunter]

Just looking for some extra ideas for when I tear the carbs and fuel pump back apart.

1967 60hp. Great hole shot with no hesitation, about 30sec to 1 min. after hole shot it somestimes (not always) falls on its face for a sec. then recovers and its good. The carbs have been rebuilt and new fuel lines. Didn't rebuild the pump at that time so I got a kit coming for that, and I'm going to tear the carbs back apart for a reclean. I'm pretty sure it's probably fuel delivery but was looking for some additional things that may cause it. Ran down the lake at all rpms (daughter driving) with timing light on and it doesn't seem to drop spark at any time.

Just to be sure I didn't do any harm... The sock type fuel filter in the glass fuel bowl didn't look real good when I 1st got the motor. I removed it and went with an inline. Will they run correctly with that filter removed?

I also didn't think about this until after I got home but I'll throw this out there. The p/u tubes are straight down into the tanks with the fill holes toward the front of the boat. If the tank is not full could it suck an air pocket during hole shot? Would there be a benefit to a longer p/u tube and route to the rear of the tank?

 

[jonesg]

Re: 67 60hp fuel issue?

"The p/u tubes are straight down into the tanks with the fill holes toward the front of the boat"

thats not clear, the fill is toward the front ? (fill means from the gas pump at the gas station).

Pickup is where? in the middle or rear of the tank?
At the very rear you might get surges from increased pressure during high G's.
My tank has the pickup at the rear but has a baffle in front of it to eliminate surges.

Anyway, you might find the surge or starving is caused by a sticky float in the carb, if the needle has a rubber tip thats outdated and will get stuck.
I would get rid of the inline filter(sometimes they cause fuel draw problems), install the proper filter and a water seperator.

 

[Lion hunter]

Re: 67 60hp fuel issue?

Sorry for not being clear. Funny how it is so clear when you write it until someone else reads it.

I have 3 plastic Atwood portable tanks. The fuel cap on the tank is toward the bow. The pickup tubes are next to the caps so they are also toward the bow. With any thing less than 1/2 tank it seems like it the pickup tube may not be in the fuel at intial acceleration until it gets on plane and levels out. Which is not that long but enough that it may suck air for a second.
So instead of the p/u tube being straight down I was curious if making it longer and running it to the back of the tank may help. Cant really turn the tanks around as fuel would run out the vent on acceleration.

The carbs were rebuilt and have new float valves but that doesn't mean there good. I'm going to pull them back apart and reclean and check that.

I just found it strange that the surge only occurs once during each accleration period. Will not happen again unless I decelerate and start over. Also pumping the bulb through acceleration has no effect on it.