5hp Honda 4-stroke/Ty Sr

[Mark]

Am considering purchasing a 5hp Honda 4-stroke for "GRACE" my Typhoon Sr. The dealer tells me this 4-stroke engine has as much thrust as a 6 or 7hp 2-stroke. Have never owned a 4-stroke. Would appreciate comments and/or experience. Thanks.



tysr@webtv.net

[Dana]

Am considering purchasing a 5hp Honda 4-stroke for "GRACE" my Typhoon Sr. The dealer tells me this 4-stroke engine has as much thrust as a 6 or 7hp 2-stroke. Have never owned a 4-stroke. Would appreciate comments and/or experience. Thanks.

___________________________________________________________________

We had started with a 2 stroke 4.5 HP on our Sea Sprite 23. It moved the boat pretty well but we opt'ed to change it for a 7.5 HP Johnson for the additional thrust we needed in the 2.5 knot current at Point Judith, R.I. The 6 HP was no longer made at the time. So I know the 5HP will move the TySr, even if it was a 2 stroke. Now the question of how much more thrust does one get. Look at the rated RPM, the prop pitch, and the diameter of the prop. That's going to be the determining factor. A two stroke 5HP may normally operate at 4500-5500 RPM with a 9 inch pitch to develop the rated HP. With my 9.9 HP the RPM drops from these values to 3500-4500 RPM and the prop increases in size from a 9-1/4 to a 11-3/4 diameter. The pitch changes also from from approx 9-1/2 to 6 inch. So along with the change of " 2 stroke" to 4 "stroke", there should also be this change in rated RPM and diameter/pitch numbers. Just compare the literature between the standard 2 stroke and 4 stroke Honda models. The Honda is a fine engine.

The engine heads are, of course, larger. I had to space my engine mounting board forward about 1-1/2 inches to make room, even though CD had designed the engine well for a 15HP 2 stroke. With the larger props, you certainly should consider at least a 20 inch skeg. Other than that, the 4 strokes are very reliable. Not prone to foaling at low RPM, does not leave a residue of oil in the carb if left for some time, etc. It is a lot easier to keep it running smooth.

Dana



darenius@aol.com

[Mark]

Am considering purchasing a 5hp Honda 4-stroke for "GRACE" my Typhoon Sr. The dealer tells me this 4-stroke engine has as much thrust as a 6 or 7hp 2-stroke. Have never owned a 4-stroke. Would appreciate comments and/or experience. Thanks.

___________________________________________________________________

We had started with a 2 stroke 4.5 HP on our Sea Sprite 23. It moved the boat pretty well but we opt'ed to change it for a 7.5 HP Johnson for the additional thrust we needed in the 2.5 knot current at Point Judith, R.I. The 6 HP was no longer made at the time. So I know the 5HP will move the TySr, even if it was a 2 stroke. Now the question of how much more thrust does one get. Look at the rated RPM, the prop pitch, and the diameter of the prop. That's going to be the determining factor. A two stroke 5HP may normally operate at 4500-5500 RPM with a 9 inch pitch to develop the rated HP. With my 9.9 HP the RPM drops from these values to 3500-4500 RPM and the prop increases in size from a 9-1/4 to a 11-3/4 diameter. The pitch changes also from from approx 9-1/2 to 6 inch. So along with the change of " 2 stroke" to 4 "stroke", there should also be this change in rated RPM and diameter/pitch numbers. Just compare the literature between the standard 2 stroke and 4 stroke Honda models. The Honda is a fine engine.

The engine heads are, of course, larger. I had to space my engine mounting board forward about 1-1/2 inches to make room, even though CD had designed the engine well for a 15HP 2 stroke. With the larger props, you certainly should consider at least a 20 inch skeg. Other than that, the 4 strokes are very reliable. Not prone to foaling at low RPM, does not leave a residue of oil in the carb if left for some time, etc. It is a lot easier to keep it running smooth.

Dana

Thanks. Upon reevaluation, ie motorwell limits, shaft length below h2oline, choose 6hp Yamaha ss because it fits with no modif. and added du



tysr@webtv.net