8HP Chrysler low rpm at full throttle

[Rabbit0074]

Please help... This is a new motor for me..<br /><br />I have a '74 8hp Chrysler outboard that does not want to perform. I run it in the barrel and it idles nice, and in forward & reverse it will rev up ok. <br /><br />Once in the water, it will rev up nice with no load, in reverse there is power... However, in forward gear, under load, it will troll ok, but when I throttle up, the rpm will increase a bit then just hold itself..seems to run at half speed. AND after about 5-10 min, it will start surging then die. Through my GPS, I clocked my 12ft aluminum going at about 8km...<br /><br />I have new plugs, points are gapped ok, The sync & throttle seem to be in line.<br /><br />Thanks<br />JCL<br />

 

[Backlash]

Re: 8HP Chrysler low rpm at full throttle

Hey Rabbit, Sounds like a fuel starvation problem to me. Is your tank vented? Have you tried pumping the bulb when it starts acting up? Let us know.<br />Backlash

 

[Rabbit0074]

Re: 8HP Chrysler low rpm at full throttle

Thanks for the reply..<br /><br />Yup, I pump the bulb and the motor will stall out. The tank is well vented.<br />I took off the carb, checked the float for clearances as per manual (library book), checked the jet (.047). <br /><br />What else can I look for?<br /><br />It's a bit frustrating csuse this is a new motor for me.<br />

 

[wau1252992]

Re: 8HP Chrysler low rpm at full throttle

Hi Rabbit,<br /> If this motor has points-condenser ignition I would be very suspicious of a bad condenser. They are easy to change and inexpensive, or they USED to be inexpensive. While you are there you could install a set of points too.<br /> It is also possible that the carb has some varnish which is causing a problem. I have used Berryman's B-12 with good results. It is an additive for the fuel. Lastly, there any damage to the prop? Sounds like a simpleton question but some damage is not so obvious. Good luck on solving your problem. Good Boating, Bill

 

[Rabbit0074]

Re: 8HP Chrysler low rpm at full throttle

Thanks Bill..<br />I will check out the points & condensers...<br />almost sounded like a bit of misfire yesterday too.<br /><br />I'm also wondering if my fuel pump needs fix'n...yet I am getting fuel pressure and squeezing the bulb will flood & Stall it out.<br /><br />Anything else to look for ?? I'm wide open for options.<br /><br />

 

[Rabbit0074]

Re: 8HP Chrysler low rpm at full throttle

HELP!!!!!!!!<br /><br />I changed piont, condensers, plug cables and still can't get my motor to work.<br /><br />I finding that it surges, and if I pull out chock half way, it seems to run better.<br /><br />I know I must have a fuel problem, but I know not where to go now? Fuel pump?

 

[JB]

Re: 8HP Chrysler low rpm at full throttle

Howdy Rabbit. I'm not very familiar with your engine. Two cylinders, one carb, right? You seem to be going in circles over probable fuel feed problems because most of your symptoms point that way, but I am going to suggest going another direction to verify a couple of things.<br /><br />I believe you are running on one cylinder. That could be fuel related, but it could also be mechanical (reeds, seals) or ignition.<br /><br />Pull each plug wire while running. If the rpm drops or the engine dies that is a good cylinder. If there is no change, that cylinder is not making power.<br /><br />ANY difference between running in the tank and running on the boat can be suspect. Do you run it in the tank with the bonnet off or on? Is that the same as when its on the water?<br /><br />Let us know what you find.<br /><br />Red sky at night. . .<br />JB

 

[Rabbit0074]

Re: 8HP Chrysler low rpm at full throttle

Thanks for replying..<br />In the tank, the motor will rev right up & empty all the water (but of course), however on the boat, the performance sucks! I try running with bonnet on & off,,,, no difference there.<br /><br />I will give the spark plug cable idea a try.. Thanks<br />Jim

 

[Yepblaze]

Re: 8HP Chrysler low rpm at full throttle

Pull the main jet and probe it lightly with some soft wire to see if there is any hardened residue you missed while serviceing.

 

[rogerwa]

Re: 8HP Chrysler low rpm at full throttle

Pumping the bulb should not kill the engine if your float valve is operating correctly. Could this be a flooding situation? Are the plugs fouled? etc..