What are the differences between a Mariner 115 and 150 In Line 6, 1987 Models. (Other than 35 HP) I guess what I'm asking is it fesible to turn a 115 into a 150? I was told the bore and stroke are the same??
Well first they quit making a 150 "inline" in 1978 and then it was just rate down toa 140 to make the BIA rating. The late model 115 shares the same block design with power port and pistons as the 150 did. Some differences in certain years are the reed blocks(less reeds) and carbs. Your engine model put out 115-120 at the prop when new and to get extra pony you will need to raise exhaust ports .125 and install a set of WKM 19 or 22 carbs as they flow a tad morefuel/air..
No not really as engine cannot benefit from the additional air/fuel as exhaust port timing is the hold back. Its hard to get extra from a inline due to the reed block and intake is so restrictive. I spent about 35 hrs on my inline cleaning,grinding and flowing and maybe gained 10hp but it helped the torque in the mid to top end range as it pulls hard from 4000 to 6500 rpm. If I can ever find another T2 or T2x that what I am going to play with!!
That's what I needed to know.. I have a '99 150 I can pick up for $800 and it runs great, (been on the lake with it, and he wants to go to a 200) I think I'll purchase it.
