Home › Forum › Ask A Member › 18HP saga continues. Can’t get past 14mph and 3,900 RPM. › Re: 18HP saga continues. Can’t get past 14mph and 3,900 RPM.
As for the adjustable jet thing, I was thinking that even if it didn’t fit in the lower pan, you could cut one short, file a slot in the end and tune it with a screw driver, or something of that nature, just to prove or disprove a point.
By the way, 18s do use a ton of fuel. Even good ones. Maybe it’s the relatively small carb bore of the earlier ones. (Pre-’69) I don’t know why; but they do. I don’t want to start a crap storm but Mark 25s are way better on fuel, in my experience.
yea I knew I would get flack over reving it in neutral. I just wanted to show that it can do it with no load, which even though it doesn’t prove anything, it does show that the motor can spin that fast. Also ignore the high idle it had in that clip, I adjusted it back down to 800 later. I was messing with the low speed mixture, and it throws the idle off everytime you do that.
You comment about the 25hp motor: I actually have a 1989 Mariner 25hp motor sitting in the garage. It’s got a water intrusion problem I’m trying to solve (already replaced the exhaust plate gaskets and there is no head on these motors) I’m sure once I fix the water intrusion on the 25hp motor and run it on my boat I’ll forget all about the 18hp. I just don’t want this 18hp motor to beat me. I keep reading about how great they are, and it is about 30lbs lighter than the 25hp motor. Since I stripped the 18hp motor all the way down, sandblasted and painted it, it looks nice and I have at ton of time in it. I’ve replaced quite a few more parts on the 18hp motor than I’ve mentioned, so in additional to time, I have quite a bit of money into this thing, so I’m reluctant to give up.