18 hp Fastwin Bogging Down

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

Ordered the parts. Gonna try to get them in 4th of July/Weekend. I'll let you guys know how it goes and if it solves the issue...

 

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

Hope everyone had a good weekend. I was able to get out to the barn and replace the coils today. Here's some things that happened/ i noticed...

Getting the flywheel off alone was a pain in the butt. Once I got i removed it i was surprised to see this:

Everything on the magneto looked good.

I checked the compression and both cylinders were just under 100, which i think is good? I removed the spark plugs and tested them the good ole fashion way: sticking a screwdriver in them and putting it near the block. Here's were things got interesting. One of the sparks was really good, strong, and blue. The other spark wasn't even there. The only way it would spark was by putting it directly on the metal.

I went back in and replaced the coils and condensers (wasn't feeling adventurous enough to do all the points at the moment). Went back and checked the missing spark and it was there; not as strong as the other but good enough.

I put the engine in the bucket and ran them on each cylinder by itself. It ran good on each cylinder so I hooked it up and it sounded like it's finally firing on both cylinders

I wasn't able to test it on the water because of rain and it was getting late. Will be doing some more testing the 4th!

Here's my question: The spark plug wires (leads) were replaced a few weeks ago. How was the guy able to get the leads into the coil if he didn't remove the flywheel (he told me he didn't check the coils, etc.)? It appeared that the lead that was missing the spark wasn't completely seated in the coil or something. Any ideas?

 

[HighTrim]

Re: 18 hp Fastwin Bogging Down

Thats impossible. lol

 

[lindy46]

Re: 18 hp Fastwin Bogging Down

It's almost impossible to replace the spark plug leads without removing the flywheel AND the mag plate, as you have to feed those wires up through the bottom of the mag plate and secure them with clamps which tighten from the bottom of the mag plate.

 

[kfa4303]

Re: 18 hp Fastwin Bogging Down

+1. It's impossible to replace the s'plug wires without removing the flywheel, then the coils. I'd be careful going back to that particular "mechanic".

 

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

Hey everyone, hope y'all had a good 4th--it rained like heck here. So i've figured out the problem with my fastwin--fuel line/pump. Today i put it in the water and it was doing the same thing as mentioned earlier: surging and no power. I accidentally took off the fuel line at the gas tank and it started hauling butt. To make sure it wasn't just a fluke i repeated it again and again with the same result. The gas tank wasn't suctioned (i even took off the little plug to make sure it wasn't). The fuel line and bulb are brand new. Do you guys think this is a fuel pump problem? Here's a video:

 

[nwcove]

Re: 18 hp Fastwin Bogging Down

not to sound negative, but any two stroke motor will rev like crazy when they start to run out of fuel. maybe try to run with the cap loose on the tank just to verify that its not a venting problem. i would guess that you have a carb issue and the motor is running to rich for some reason. jmo

 

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

not to sound negative, but any two stroke motor will rev like crazy when they start to run out of fuel. maybe try to run with the cap loose on the tank just to verify that its not a venting problem. i would guess that you have a carb issue and the motor is running to rich for some reason. jmo

I ran it without the cap and still same issue. I also noticed that the bulb was pretty hard when running and when i pumped it it flooded the engine and killed it...i just had the carb rebuilt so i hope that's not the problem

 

[nwcove]

Re: 18 hp Fastwin Bogging Down

your fuel pump could be leaking excess fuel into the top cyl, or the float needle isnt seating quite right? pumping the bulb should not flood the engine if everything upstream is working properly.

 

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

your fuel pump could be leaking excess fuel into the top cyl, or the float needle isnt seating quite right? pumping the bulb should not flood the engine if everything upstream is working properly.

I forgot to mention that i did notice a little gas slick around the motor when i was starting it. And before i launched the boat i put the motor up and there was some gas leaking into the back of the boat. I couldn't really tell where it was coming from but the carburetor looked a little wet. I don't know enough about boat motors to be able to take apart the carb (although i could probably switch out a fuel pump--and i was able to do the coils and condensers). Is it safe to say that the motor is flooded or getting too much fuel when the fuel line is connected? Would adjusting the high speed or low speed needle effect this? Also, i have a fuel mixture knob that appears to be on the low speed needle? Am i correct that the low speed needle is the same thing as the fuel mixture knob?

 

[geoffwga1]

Re: 18 hp Fastwin Bogging Down

That is correct,on that motor there is only one mixture adjusting knob at the top of the carburetor and it's the low speed needle.The high speed jet is fixed and there's no adjustment.Do not be afraid to take on the carburetor and rebuild it ,it is not hard as it's a very simple piece of kit but it MUST be clean,and I don't mean just shiny on the outside.Remove it from the motor,undo the four screws holding the bottom bit onto the top bit ,that's the float chamber,check the float is not gaslogged if it is one of the old cork ones and that it is just about level when you hold the carb upside down.Before starting get yourself a carb kit,right here at iboats,then go to the top secret files at the top of the page where you'll find a link that will lead you right through it.As for your spark issue,that could be due to a failing coil or capacitor or a lousy plug.The spark(both of them) should jump nearly a half inch air gap using a spark tester(5 or 6 bucks at Autozone ,I made my own) if you don't get that sorted you will always have issues.Like I said don't skimp and do it all methodically and you will end up with a great little motor,I love mine.

 

[jonbellamy]

Re: 18 hp Fastwin Bogging Down

That is correct,on that motor there is only one mixture adjusting knob at the top of the carburetor and it's the low speed needle.The high speed jet is fixed and there's no adjustment.Do not be afraid to take on the carburetor and rebuild it ,it is not hard as it's a very simple piece of kit but it MUST be clean,and I don't mean just shiny on the outside.Remove it from the motor,undo the four screws holding the bottom bit onto the top bit ,that's the float chamber,check the float is not gaslogged if it is one of the old cork ones and that it is just about level when you hold the carb upside down.Before starting get yourself a carb kit,right here at iboats,then go to the top secret files at the top of the page where you'll find a link that will lead you right through it.As for your spark issue,that could be due to a failing coil or capacitor or a lousy plug.The spark(both of them) should jump nearly a half inch air gap using a spark tester(5 or 6 bucks at Autozone ,I made my own) if you don't get that sorted you will always have issues.Like I said don't skimp and do it all methodically and you will end up with a great little motor,I love mine.

The carb kit for my year (1968) doesn't include a float, but the later years do. Is there a reason for this? Do i need to buy a new carb kit if i just had the carb done at a shop like 3-4 weeks ago?