View Full Version : 283 F New Engine Problem
08-20-2007, 01:02 AM
"It is driving us nuts, new motor, new heads, new everything. Flywheel forward engine, set timing like it says, wouldn't start. Then we set it up like a regular Chevy Engine, using one aft instead of forward, it runs but has no power, back fires through carb and exhaust when power is applied. We have set timing, tried two different carbs, a rebuilt rochester and Holley 650 CFM, both mechanical and electric fuel pump, starts but will bog down and backfire when it starts up. Checked the mechanical advance on the distributor, it is fine, checked points, changed it out. We are stumped. Fuel is new and good. ANY IDEAS, HELP!!!!!!!!!!"
08-20-2007, 12:54 PM
"New motor eh? I would ask "where did it come from"? Is it the proper rotation, or did you get one that is supposed to spin the other way?
Flywheel forward should spin LH when looking at the flywheel, so the prop spins RH.
In any case, here is some info that may help a bit. A 650 carb is grossly over-carbed for a 283, by the way. A 600-cfm is what CC put on my 427 enignes. Engines that spin 4000 rpm have no need for big carbs.
08-20-2007, 01:04 PM
This was a rebuilt engine out of Canada at a place which specializes in CC. The engine spins RH when looking at the prop. Everything seem in order on rotation.
We went back the original Rochester Carb.
08-20-2007, 02:36 PM
"If it is a flywheel forward motor and the prop is spinning RH when viewed from behind the boat, then you have a LH motor, which is installed backwards, to make the prop spin RH. It may be called a RH installation, but you have a LH motor, because the rotation of the flywheel is what makes that determination.
Be sure to time the boat according to the LH spec, and not the RH spec. See the diagrams in my reference link. Note the direction of flywheel rotation in these diagrams.
If you have it timed wrong, then cylinder 1 and 6 are still timed right and they'll try to fire. Not too good for the motor.
Also, did the distributor come with the motor? I don't think a reverse gear will work on the standard cam, but the distributor should be spinning clockwise.
When you said you timed it "like it says" and it would not run, and then you "set it up like a regular Chevy Engine, using one aft instead of forward" this has me puzzled.
Please look at this diagram again, closely, noting where the flywheel is on a LH motor, set your motor up accordingly, and I think you'll fix the problem. I think you have the wires all crossed up.
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