Reviving Fastwin 18hp.

[renns]

I'm looking for some info on setting up the carb throttle linkage and cam on my latest project. There are two notches on the cam itself, and also two notches on the plate it mounts to. What do they signify, and are they supposed to be in alignment? Also, the throttle lever is loose on the shaft, so I'm wondering how to go about setting that up. I assume that will determine idle speed? And finally...if I crank the tiller throttle all the way to slow, the roller pops right past the end of the cam and rides on the mounting plate. Again...wondering if setup is off. If someone has a picture of how it's all supposed to line up, that'd be great! I have had it running, but want to get this setup sorted before I do any more tuning.

 

[hardwater fisherman]

The 2 upper marks are ignition timing marks. And the 2 lower ones on the cam are for the carb sync. The throttle plate should start to move when the roller is between the marks. And you adjust it with the screw you have circled in your 1st photo.

 

[F_R]

Um, don't you adjust the cam/roller pickup by loosening the screw holding the cam and move the cam in or out? Or is this one different?

 

[hardwater fisherman]

Okay fair enough. I was thinking of my 25 hp and my 40hp. What does the screw on the throttle plate shaft do then?

 

[renns]

Thanks for the info. I ended up tightening the throttle shaft lever screw with the tiller twisted to slowest possible position. The motor started and ran at fast idle with a bit of tweaking of the low speed mixture screw. Another cause of concern, though, is that there seems to be small leak at the crankcase part line. See pic for leak location. This motor has an unknown history. It came with a cottage we purchased last year. Compression was good, but ignition and recoil needed repair. I did those repairs and put an electric start setup on it. Was hoping to use it on the lake this summer.

 

[hardwater fisherman]

According to an online manual 1969 through 1972 is adjusted as I said. And looking at parts diagrams the throttle shaft screw was introduced in 1969. You may be right though as I am wrong often.

 

[Chinewalker]

The seepage at the crankcase seam is not uncommon on older motors. The sealant gets old and dries out, then is blown out by crankcase compression. Over time it will get worse, to the point where the motor won't idle well due to air leak. Not hard to disassemble and reseal, but is probably best to save for winter project.

 

[F_R]

According to an online manual 1969 through 1972 is adjusted as I said. And looking at parts diagrams the throttle shaft screw was introduced in 1969. You may be right though as I am wrong often.

OK, I looked it up in a 1972 OEM Factory manual and you are correct, at least as pertains to 1972. Sorry for the confusion.

 

[renns]

The seepage at the crankcase seam is not uncommon on older motors. The sealant gets old and dries out, then is blown out by crankcase compression. Over time it will get worse, to the point where the motor won't idle well due to air leak. Not hard to disassemble and reseal, but is probably best to save for winter project.

Is there any external sealant that could be used to seal that seam for a season? I know that'd be a bandaid solution at best, but I was hoping to get out on the lake with the motor a few times this summer and don't have time to attempt a full disassembly and re-seal until next winter.

 

[F_R]

Minor leakage won't affect it much at all. More messy than anything. If it's leaking enough to affect the running, it needs to be fixed properly.

 

[Chinewalker]

As FR said, it won't do much for now, but it's not going to fix itself. As I noted, save it for a winter project.

 

[renns]

OK, thanks for the help!