1989 GT150 Max Spark Advance?

[sunrize on the water]

Using the factory service manual under synchronization and linkage adjustments on page 1-41 in the NOTE it states:

Do not use propeller or flushing device to perform this procedure. I must use the correct test wheel?

I think I understand a test wheel applying proper torque to the motor at high rpm's.

Question's are:

1. Can I purchase this item at a reasonable cost?
2. Is there an alternate way to perform this task?

Sincerely,

Craig

 

[Bosunsmate]

Re: 1989 GT150 Max Spark Advance?

Try this
http://forums.iboats.com/engine-fre...q/joe-reeves-wot-timing-procedure-228183.html

Ive never used a test wheel- too expensive

 

[boobie]

Re: 1989 GT150 Max Spark Advance?

You can make your own test wheels by cutting the ends off of a damaged prop. Been there.

 

[sunrize on the water]

Re: 1989 GT150 Max Spark Advance?

boobi,

Can you be a bit more specific please. Thank you.

 

[emdsapmgr]

Re: 1989 GT150 Max Spark Advance?

If you have a factory service manual, you should be able to determine the part number of the original factory test wheel. Occasionally you see them advertised on Ebay. They are hard to come by. Usually folks use a number of different methods to set the WOT timing. 1. Factory test wheel. 2. Lower the boat and trailer into the water at the boat ramp. Submerge the engine so that just the prop and cooling holes in the lower unit are underwater. Start the engine and rev to 5000, making absolute sure the water inlets don't starve for water. 3. Set the timing on the boat with a friend driving (usually fairly risky.) 4. Use the above-mentioned Joe Reeves method. It works well and will usually get withing the degree tolerance of the factory manuals. Years ago, I saw an OMC master tech use the method 2, above a couple of different times.

 

[boobie]

Re: 1989 GT150 Max Spark Advance?

Emds, didn't you ever hear of clipping off the blade tips to make your own test wheel ?? Mercury did this years ago in their service schools and OMC did in their test sites when the motor was stationary and being run for long term running at the same rpm.

 

[emdsapmgr]

Re: 1989 GT150 Max Spark Advance?

Another good option if you clip the prop correctly to maintain proper loading. Just requires an old prop you have no use for.