swiss

Hi guys. I have a 92 Chaparral 2500sx. It is was built from the factory with a 7.4 Yamaha sterndrive. I am having trouble trying to set the timing on this thing. I replaced the engine last year (cracked block) with a mercruiser 330hp with mercruiser accessories and carb all factory but i used the ignition from yamaha that was already in it. I can not find any info on how to get it into base timing mode. Yamaha calls for 13' of timing with the jumper but i dont know how to jump it into base timing mode... also should i still use the 13' with the mercruiser set up?
Any help would be greatly appreciated!

Thanks,

SWISS

BUP

iTrader: (9)

Do you still have the Yamaha Hydro drive ? That drive has a hydraulic clutch system that is very smooth. That was a great outdrive and very rare. I was trained for the Yamaha Sterndrives in the very early 1990's but have not seen any in about 10 years. You can not get parts for these apps in the USA.- NONE only if anyone on ebay has them

Anyways back in the day stock OEM Yamaha used an EST ignition set up. EST = Electronic Spark timing system. It is best to buy the EST timing tool for about 10 bucks - you can even buy it thru an auto store.

Warm engine up fully then adjust idle speed to around 750 rpms in N for this app. Pull out widest connector from the distributor then Insert the timing tool in the widest connector in the distributor and connect the timing tool alligator clip to a good 12 v source - on the timing tool it will be a short alligator clip lead so you can add to it and connect to the positive on the battery with another jumper lead.

now check your timing with your timing light hooked to the number one spark plug. If needed loosen distrib hold down bolt then Adjust timing to 13 degrees BTDC if it is not already. after that lock down distrib clamp bolt and recheck timing again to make sure nothing moved. Then pull out EST timing tool and clip from your 12 v source and reconnect ignition connector back into the widest connector in distributor - . then of course remove your timing lite

swiss

Yep still have the hydro drive! That thing works great and shifts smooth, smooth, smooth! I have found parts for it in random places on the old interweb. You just have to do some digging. There is a guy in florida with a ton of used parts for these things. From what i have read they are pretty heavy duty, they put them behind diesels with no issue so we are going to run it until catastrophic failure and switch to mercruiser. Hopefully with proper maintenance it will last a long time.
So will o'rielly have this est timing tool?
Thanks for the help!

BUP

iTrader: (9)

I bought my EST timing tool thru Volvo and Yamaha back then and thru out the years. I probably have 20 of them. You can call around or order them like anything else off the net. Even when you buy some EST ignition set ups the timing tool comes with them.

swiss

Thanks man!
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