tfbrown1270
Petty Officer 1st Class
- Joined
- Sep 5, 2003
- Messages
- 202
OK...(long post sorry)
this new to me motor was rebuilt over the winter, new .040 over size pistons, rings, rebore, new water pump impeller, carbs rebuilt, link and synch by the marina mechanic.
It was in the test tank at the shop on the dyno when I first saw it run..it made the required amount of psi during the test and ran both in gear and in neutral and it ran like a Cadillac before I took possession. I then dragged it nearly 3 hours to the lake.
Here it ran poorly at idle. I was perplexed so I called the shop and advised it was idling at about 500 rpm and dieing regularly with a lean sneeze. I then discovered (see picture) that the timing arm at the top of the throttle shaft was not locked with the lock nut but free to turn.
They suggested it may have vibrated out of position during the long bumpy drive to the lake.
Judging from the picture (which I showed them) they recommended I turn the shaft out (that is so it draws the arm forward towards the bow of the boat (to the right in the picture) about 1/4 inch and see if that improves things as they believe the idle timing is "too advanced" causing the lean sneeze. It runs great at any throttle setting other than idle, except that max rpm is 5000...that was another post!
I will try this this coming weekend.
Additionally they suggested I could move the idle higher by turning the knurled wheel on the throttle cable shaft where it goes through the cowl to draw the throttle a bit open; this is seen in the lower right of the entire engine picture (this as opposed to using the idle adjust screw???)..anyway to their credit they would be happy to look at it in the shop but thats a long and expensive drive from the lake and back.
I posted a video of the engine running and then stalling on youtube under my user name (kenorakq)...this may help if you are interested enough to watch...
Thanks (oh I posted at about 3:00 pm Tuesday May 29th (Central) so it may take awhile for the video to be watchable.)
ANy suggestions? Am I on the right track?
this new to me motor was rebuilt over the winter, new .040 over size pistons, rings, rebore, new water pump impeller, carbs rebuilt, link and synch by the marina mechanic.
It was in the test tank at the shop on the dyno when I first saw it run..it made the required amount of psi during the test and ran both in gear and in neutral and it ran like a Cadillac before I took possession. I then dragged it nearly 3 hours to the lake.
Here it ran poorly at idle. I was perplexed so I called the shop and advised it was idling at about 500 rpm and dieing regularly with a lean sneeze. I then discovered (see picture) that the timing arm at the top of the throttle shaft was not locked with the lock nut but free to turn.
They suggested it may have vibrated out of position during the long bumpy drive to the lake.
Judging from the picture (which I showed them) they recommended I turn the shaft out (that is so it draws the arm forward towards the bow of the boat (to the right in the picture) about 1/4 inch and see if that improves things as they believe the idle timing is "too advanced" causing the lean sneeze. It runs great at any throttle setting other than idle, except that max rpm is 5000...that was another post!
I will try this this coming weekend.
Additionally they suggested I could move the idle higher by turning the knurled wheel on the throttle cable shaft where it goes through the cowl to draw the throttle a bit open; this is seen in the lower right of the entire engine picture (this as opposed to using the idle adjust screw???)..anyway to their credit they would be happy to look at it in the shop but thats a long and expensive drive from the lake and back.
I posted a video of the engine running and then stalling on youtube under my user name (kenorakq)...this may help if you are interested enough to watch...
Thanks (oh I posted at about 3:00 pm Tuesday May 29th (Central) so it may take awhile for the video to be watchable.)
ANy suggestions? Am I on the right track?
