Chrysler 35 HP starved for fuel?

[Jkoosh]

Thought I would check on here to see if anyone ever had this problem before...

So I have a 1974 35 HP engine on a 16 ft aluminum boat, ran nearly 100+ hours last summer, no problems all year.

This year, brought it out for the summer and idles fine, revs fine when not in gear.

Took it out on the water, and it will rev to about 1\4 throttle, but any further and the engine loses rpm, and will die if I don't back off on the throttle. It will run for as long as I want at idle and a tad higher, but will show signs of losing rpm as I slowly give it higher throttle.

I'm thinking it's starved for fuel, but any suggestions on where to start? My thoughts are carb float, maybe fuel, but anyone else have this problem before?

On a side note, I have read to install a fuel filter between the fuel pump and carb, is this a general consensus for our old engines? Thinking maybe this could help stop the problem if it is a clogged carbeurator...

Thanks for all the help guys!

 

[Frank Acampora]

You need to check the complete fuel system from tank to carb. You should also remove the carb and clean it. WD40 and pipe cleaners are pretty good.Check and replace the fuel pump diaphragm. It may simply be old and not capable of delivering enough fuel to run at much above idle.

 

[Jkoosh]

Hey Frank,

Thanks for the advice, I went through and replaced the fuel pump diaphragm and cleaned the carb with spray, put it in the water and ran it, the engine had no issues, and I put it on the trailer.

I went to take it out the other day, and low and behold, the same issue presented itself...

I took the carb off the engine, gave it a hard clean again, then reassembled and put it back on... Now for the funny part...

When I put the trailer in the water, I started the engine, and then ran it while still on the trailer, and it ran to full throttle without any problems. It held RPM and seemed fun as I could gun the throttle or work it slowly and the engine never bogged down.

Then I took it off the trailer figuring it was running well....but it wasn't. It acted as it had in the first place.

Should I take the carb apart and try to remove the main jets and press it out to clean it?

Does the diaphragm only go on a certain way? or can it be flipped and put on either side up?

Thanks guys.

I can try and post a video of it bogging out later tonight to show the problem visually if that might help....

 

[Nordin]

Does it rev up if you prime the bulb? If it does there is a problem of the fuel delivering.
Try to give it a touch of the choke and see what happens. If got improvment there is a problem in the carb.

 

[wickware]

I have a 1970 35 hp Chrysler since 1984 that has always run well but needed tweaking to run better at times

Was it stored with Stabil or Etc treated fuel and running fresh treated fuel now?
When is the last time you checked ignition points and plugs? Clean Points was my #1 prob.
I have a clear inline filter between tank and f/p that I can see to know I gave solid fuel.

 

[jerryjerry05]

Replace all the hoses and squeezie.
You running off a remote tank? Vent open?
Change tanks, check for water in the tank.
Ethanol eats older hoses.
Install a filter between the carb and pump.