85 model johnson 235 with no low end power

[jself123]

i have a 17 foot vip ski boat with a johnson 235 outboard on the back. the problem i am having is plaining out the boat. once the boat is plained out it has plenty of power all the way through the throttle. i had the carbs gone through at 2 local shops and no help, they say it is normal for a 235 but i am hard headed and dont believe a 235 horsepower motor will barely plain out a 17 foot boat. it has a 21 pitch prop currently but i can put a 17 pitch and it helps a lot. any suggestions.

 

[tashasdaddy]

Re: 85 model johnson 235 with no low end power

check you compression. proper trim and height is important. what are your wot rpms with each prop. the 17 will give you a much better hole shot. your motor needs to be trimmed all the way down to get on plane, then trimmed out for speed. if you have a bunch of people or weight in the stern, it will take forever to get on plane. balance your load.

 

[jself123]

Re: 85 model johnson 235 with no low end power

i have a 17 foot vip ski boat with a johnson 235 outboard on the back. the problem i am having is plaining out the boat. once the boat is plained out it has plenty of power all the way through the throttle. i had the carbs gone through at 2 local shops and no help, they say it is normal for a 235 but i am hard headed and dont believe a 235 horsepower motor will barely plain out a 17 foot boat. it has a 21 pitch prop currently but i can put a 17 pitch and it helps a lot. any suggestions.

with the 21 pitch prop wot rpm is about 6k i am not sure on it with the 17 it has been a while since i ran it. i borrowed it but i just ordered one. the compression is good. what wot rpm is safe to run

 

[tashasdaddy]

Re: 85 model johnson 235 with no low end power

5500-6000 rpms.

 

[elhombre]

Re: 85 model johnson 235 with no low end power

mabee you have spun hub on the prop-

 

[jself123]

Re: 85 model johnson 235 with no low end power

i have a 17 foot vip ski boat with a johnson 235 outboard on the back. the problem i am having is plaining out the boat. once the boat is plained out it has plenty of power all the way through the throttle. i had the carbs gone through at 2 local shops and no help, they say it is normal for a 235 but i am hard headed and dont believe a 235 horsepower motor will barely plain out a 17 foot boat. it has a 21 pitch prop currently but i can put a 17 pitch and it helps a lot. any suggestions.

i had a 21 pith aluminum prop that was turned down to 19 pitch and does the same thing. ialso have a 21 pitch ss prop. i ordered a 17 but i dont want to over rev engine. also wandered about timing. it says 30 on motor but what rpm do u set that at. and can that cause my problem

 

[emdsapmgr]

Re: 85 model johnson 235 with no low end power

While the 235 is a high port engine, (less bottom end) it should have plenty of power to run your 17' boat with a 21 pitch prop. I'd be looking for compression numbers near 110 on a healthy engine. If compression is in the 90 range, that can make the difference. Make sure the engine is not mounted too low on the transom. It should pull strong up to 6000. You may want to run some engine tuner through it, then re-run it.