Upgrading my 1982 Johnson 90 2 stroke to a 2003 Suzuki 70hp 4 stroke

[ib18]

I am planning to Upgrade my 1982 Johnson 90 2 stroke (300 pounds? J90MLCNB) to a 2003 Suzuki 70hp 4 stroke (348 pounds?) on a 1974 wellcraft airs lot 165

2 questions:
1. Is my new Suzuki too heavy for my boat transom?
2. DO I need to seal and drill new holes to mount the Suzuki 70 hp?

Thanks for your help in advance.

 

[82rude]

What hp is she rated for?Id say no the suzy is not too heavy.Holes should match up mine did no problem.I went form a 76 or so 85 johnson to a 2011 60hp .All holes the same.Not exactly sure what year it was but everybody went to a industry standard pattern.

 

[Silvertip]

Not exactly an upgrade except for the model year. Dropping 20 HP and going from 2-stroke to 4-stroke also results in some performance loss. Fuel economy may not improve as much as you would expect because you will be running the 70 with far more throttle than with the 90. Fuel economy is directly related to throttle position. If the boat had a max HP rating for the 90, then you can expect to run the 70 with fairly high throttle settings.

 

[jimmbo]

Don?t expect it be any ball of fire either

 

[racerone]

I thought the 90 Johnson was running just fine.-------You would surely need a factory manual to work on the Suzuki motor.

 

[ib18]

yes, Johnson 90 is just fine but love to upgrade to the 4 cycle to improve on gas mileage. Too much no wake zone area here on the Potomac river so looking for a kicker motor or upgrade to a 4 stroke if I can get a deal.