5 HP Gamefisher Carb Ignition Sync

[ben2go]

1980 Eska built 5 HP Gamefisher
Model# 217-585460
Tecumseh air cooled 1 cylinder power head.

I have fuel and bright blue spark,but my engine just pops through the exhaust column.When I changed the points and condenser,I set the points per service manual.I couldn't check the carb ignition sync.I understand that as the carb is opening up the ignition advances at the same time.I just don't know how to set the advance in relation to top dead center.I also don't know how much or how fast the advance needs to come in.Everything operates off rods and a cam.There is a special timing plate tool that is used to help set the timing but I can not locate one.Tecumseh, of course,no longer makes them.Sooooo, how can I set the timing without the plate?How many degrees of timing at idle and whats the max degree of timing at wide open throttle?If I had these two numbers,I could use a degree wheel to set it up.Thanks in advance for any help.

 

[Meals_on_Reels]

Re: 5 HP Gamefisher Carb Ignition Sync

if you can shoot me the engine type number ( on the tag on the block something like 640-18 or 639-17, etc.) I can give you the timing. use a dial caliper through the spark plug hole, locate TDC and the turn the engine back to whatever the spec is. from there the process is all about the throttle cam. you will need a continutity tester to see when thepoints open and close in order to be able to set the stops and cam.

 

[ben2go]

Re: 5 HP Gamefisher Carb Ignition Sync

Could it be 643-29?My engine doesn't have a tag.It was broken off long ago.Sears has the engine number list as 643-29.

 

[Meals_on_Reels]

Re: 5 HP Gamefisher Carb Ignition Sync

All 643 motors have a timing of .085 inches BTDC. Unfortunately the 643-29 isnt listed in my manual which is the same problem I had with my 7.5HP. It does appear that 98% of the 643 motors use this timing proceedure.

a) apply small ammount of E.P. lithium grease to the contact area of the friction screw. Do not turn the screw into the radius of the stator collar

b) Install the stator with the operating handle pointed in the direction of the carb. be sure the throttle post on the carb in on the outside area of throttle actuating cam.

c) Tighten the friction screw to 5-8 inch lbs torque for twist grip models and 12-15 inch pounds for other models.

d) Install the points, if necessary. Adjust the point stationary base for a .020-inch point gap on the high side of the cam, then close the points and clean. Use a squarely cut piece of bond paper to clean the points.

e) Use a dial indicator through the spark plug hole

f) Find TDC while rotating the crankshaft

G) Find the correct BTDC dimension (which is .085)

H) Apply correct dimension to the engine.

I) Install the leads of some cotinuity device on the point terminal and to the ground

J) Move the stator counter-clockwise, advancing the timing until the continuity reading breaks and reads zero. Tighten the stop bracket so the stator won't move ny further counter-clockwise.

K)Loosen the cam locking screws just enough to allow adjustment of the cam. Move the cam to open the throttle completely WITHOUT causing any binding with the throttle post.

L) Todetermine the idle-speed throttle cam pick up point the proceedure is as follows:

1)Use dial indicator to find the .003 inch after to dead center piston postion.
2) With continuity device conected to the the point terminal post and ground, retard the timing ( move lever Clockwise) until the points close and continuity is established. The operating lever should be at the full-run position to start. Find the point where continuity breaks, then hold the magneto position.
3) Move the throttle actuating cam right side so that the cam just touches the throttle post without actually moving it. Tighten retaining screw to hold the position.

Hope that helps ya out a bit. Good luck!

 

[ben2go]

Re: 5 HP Gamefisher Carb Ignition Sync

Thanks.I'll try to do it that way.