15HP Bigfoot vs 20HP Four Stroke

"I just bought a 2005 Bayliner

"I just bought a 2005 Bayliner 160, which has a weight of 1300 lbs. Because of the lake I use I am restricted to a 20HP engine. I had the original engine (Mercury 50HP)pulled off at purchase. I am now in search of a new or newer engine. I have a chance to buy a 1883 used Mercury 18HP, 2 stroke engine. The age bothers me. I was wondering if a 18HP, 2 stroke will push the boat just the same as a 20HP 4 stroke.I then was thinking of using a new Mercury 15HP Bigfoot, 4 stroke, which has a larger lower unit for pushing. Does anybody have any comments on which way I should go with this."

"John, each of the three engin

"John, each of the three engines you list would produce roughly the same top end results with that particular boat - somewhere in the 17-20 mph range under perfect conditions.

Each however, have their advantages and disadvantages.

The 18 horse 2 stroke will have better "kick" than either of the 4 strokes and if you are looking to cheat a bit, the 18 can be turned into a 25 with a simple carb change - although that would violate EPA laws

The bigfoot will get the boat moving better than the 20, but not as quickly as the 18.

And the bigfoot's top end will be less than satisfatory without using a prop big enough to offset it's ability to "get out of the hole" - but when it is absolutely flat out, you may get 2 more mph out of the 20 horse.

In the longer run, the 4 strokes will cost you more in maintenance that the 2 stroke simply because there is more to go wrong.

Personally, I wouldn't buy a 4 stroke, and definately not a used one - would take my chances with the 2 stroke even if it is 25 years old...."

"Thanks for that great info. I

"Thanks for that great info. I have another question if you don't mind. My boat was all rigged for a Mercury 4 stroke. All controls are still on the boat, with a key start in the dash and a side mounted throttle. Can the dealer hook up say the 18HP Mercury without removing all the controls and harness from the previous engine. The 18HP would be a two stroke,or do I have to use the harness and controls that come with the 18HP? Is this a big job?"

"John, you may be able to use

"John, you may be able to use the existing control - it will mostly depend on whether or not the wiring harness can be easily adapted.

The throttle and shift cables should either work fine or simply need a retro-fit on the end (engine end) in the form of a new connector.

Otherwise, depending on subtle differences, especially if it is either a Merc control (or a Generic that can be used on different models - such as US Marine) it should be an easy hook-up in most cases."