68 rude starflite 100hp

[kgfielder]

i recently bought a boat with a 100 68 rude. the mechanic who i bought it from said it ran great for bout two years and then he started having problems with it cutting out at mid to full throttle. he believes it to be not getting enough fuel because he took the carbs apart and cleaned them and converted it back to points, and replaced distributer cap and plugs and wires. he also said it could be sucking air from tank. any incite on what the prob might be. he put a used 12v fuel pump on instead of a engine mounted diaphragm pump so the fuel lines now go strait from tank to pump to engine could this be a problem? i am new to boating soo any help would be appreciated. i replaced the fuel tank and connection.

 

[outboarddan]

Re: 68 rude starflite 100hp

i had a motor do somethig similar it would cut out once i opened it up, but it was electrical, i disconected the tach and then it worked great, not sure if this helps

 

[Willyclay]

Re: 68 rude starflite 100hp

Welcome to iBoats Forum. Some very smart and experienced people here to help you. I have a 1968 100HP Johnson. We need to get a better idea of the "cutting out" problem at mid/high RPM. Does it reach the mid/high RPM range and then start misfiring/skipping OR is the engine bogging at WOT and never reaches the mid/high RPM range? Also, I personally would not want the 12V fuel pump on my engine for safety reasons. I lived through one incident of a bilge full of gasoline and try to warn others of the risks of a pressure fuel system versus a suction system. Good luck and be safe!

 

[kgfielder]

Re: 68 rude starflite 100hp

thanks for the info, we rewired it today and boy o boy was a mess. old wires and bad connections ended up tearing every thing out and replacing it all. also found out that our fuel pump is working but the bilge is not lol, its turning over but not starting so tomorrow i am going to replace the spark plugs. im still curious to if maybe the 12v fuel pump is not supplying enough gas for the higher rpms? what do the diaphragm fuel pumps run and what bout bilge pumps ne one know?

 

[jimmbo]

Re: 68 rude starflite 100hp

Are you sure it is a 68? In 68 the trigger assembly was under the flywheel, the 67 used a seperate belt driven distbutor. As for the 12 volt fuel pump, bad idea.
My dad used to have a 1965 90hp which was the forerunner to your 100hp , it too used stall when run at full throttle. It turned out to be the orings in the fuel line connectors allowing air into the fuel line. New orings fixed it

 

[jay_merrill]

Re: 68 rude starflite 100hp

The first thing that I would do to this motor is to return everything to stock configuration. Start by getting the model number off of the data plate, get the serial number off of the "freeze plug" on the powerhead and then figure out just what you have. The members here can help you with info on the two numbers. Once you do all of that, go find a service manual and rip out all the modifications.

I wouldn't be surprised if most or all of your problems are directly related to poorly done modifications.

 

[kgfielder]

Re: 68 rude starflite 100hp

i dont know ne thing bout boats soo u lost me on the fly wheel and belt drivin distributer? as for what year it is i only know what i was told and given a manual for the 68.

 

[kgfielder]

Re: 68 rude starflite 100hp

also how hard is it to replace the fuel pump, and how do i knjow if my electric choke is working or not, also i notices with this 12v pump on there the engine floods too easy i believe because as soon as the key is on the pump is pumping soo there cant be any hesitation when starting or it will flood.

 

[jimmbo]

Re: 68 rude starflite 100hp

If you have the pump and crankcase gasket or pressure hose(depending on which year it is), and a Good Service Manual not too hard. The 12 volt fuel pump puts out way more pressure than the original fuel pump, that's most likey the reason the carbs flood so easily.

What is the Model # of this engine?

 

[kgfielder]

Re: 68 rude starflite 100hp

100883b, thanks for the info i need it, im having issues now with finding the sparkplugs to fit it all the parts dealers catologs are not matching what the manual says.

 

[jimmbo]

Re: 68 rude starflite 100hp

It is a 68. Distributor is under flywheel. Fuel pump is the later style and is mounted on the port side of the lower cowl and is connected to the drankcase by a pressuse hose. Spark plugs were in 68... Champion L-19V or AC V40FF.

Chapion website says.... L77JC4 @ 0.030" or For Commercial service use 876/QL16V.

The automatic choke is actuated electrically by a solenoid. The choke electrical control is provided with two positions: With choke control ON, battery current is supplied to the solenoid which closes the choke valves; however, when engine is running, suction will partially open the choke plates. With the choke control in AUTOMATIC position, battery current is supplied to the solenoid via the thermal switch in the water by-pass cover. When the motor is cold, the thermal switch will pass the battery current, but when the motor reaches operating temperature the thermal switch will open and stop current flow to the solenoid.
The thermal switch can be checked with an ohm meter or continuity light. Current should pass through switch when cold but stop when temp reaches 145 degress F.

 

[kgfielder]

Re: 68 rude starflite 100hp

thanks jimmbo, i put new spark plugs in today and it still does the same thing cranks but not starting, and im pretty sure my selenoid for my electric choke is bad it doenst seem to be moving at all when the switch flipped could be the wiring too have have my buddy take a look at that, could the engine be too cold after sitting all winter would it be wise to use an engine starting fluid to get it to at least start. i just want to know if it will run at all cuz if not i will pry sell it.

 

[jimmbo]

Re: 68 rude starflite 100hp

No, no, no. Do not use starting fluid on a 2 stroke. It will wash the oil off the crankshaft and connecting rod bearings, plus being that ether ignites like diesel from compression heat although at a lower temp, it could ignite inside the crankcase instead of making it to the combustion chamber.


As for the starting. An engine needs three things to run; an air-fuel mixture that is combustible, compression, and finally, spark at the right time.

 

[kgfielder]

Re: 68 rude starflite 100hp

whats a motor like this worth for parts any one know?

 

[jimmbo]

Re: 68 rude starflite 100hp

whats a motor like this worth for parts any one know?

Whatever you can get for it, is what it's worth

 

[kgfielder]

Re: 68 rude starflite 100hp

aight i might take it to have some one look at it and tell me whats the deal and weather its worth fixing. thanks all for your help. peace