89 Johnson 150

[iron21]

hi, i'm in the process of purchasing a used boat. after looking at a few, i've found a 1990 bonito open bow w/ an '89 Johnson 150 vro for a very reasonable price. Its a 20' boat,a relatively light hull. The owner says it will do 32-34mph(5,000 rpms) at wot. I only have i/o experience, but that seems unusually slow for a 150 hp outboard, even considering its an '89. Should it be doing for like 45-50 mph? is this the sign that a rebuild will be needed soon? do you know off hand what the compression should be for this engine? I'm going to check it out tomm or the next day and would appreciate opinions or advice as this would be my first outboard.
thanks!

 

[JB]

Re: 89 Johnson 150

Outboards do not get slower because they are old, iron, and '89 is not old. 150HP is not a lot on a 20' boat and 5,000rpm is not the best WOT.

Compression should be pretty even, within 10%-15%, across the board. I would look for 100PSI range, but guages and technique vary too much to set a standard for psi.

Sounds like the boat could use some fine tuning of the rigging and maybe the prop, but I would not expect to get much beyond the upper 30s in WOT mph.

 

[tashasdaddy]

Re: 89 Johnson 150

according to NADA Boats the Bonito was not built in 89 and the don't show a model 1990. they show 1988 last production and 190 weighed 1500 lbs.

i would do some more investigation, but i would expect high 40's. boat may be water logged. have it weighed and calculate addition of motor and trailer weight, before buying.

 

[iron21]

Re: 89 Johnson 150

thanks for the replies..i'm gonna check the compression and take it out for a water test when i get there. i was thinking too, maybe the owner was wrong about the top end speed. i'll bring my hand held gps and see what happens.
as far as the year, its a '90 boat with an an '89 engine..i dont know whay nada boats isnt showing that. Ive found nada. com to be inaccurate when it comes to older boat. i really try avoiding nada because i've gotten bad information in the past as well.