frustrated johnson owner

[frustrated johnson owner]

i bought a 86 179 stratos project boat last summer... i have been working on getting it tournament ready all winter.... have done some engine work,, like stator, power packs, also a new lower unit.... have taken it out a couple times to run it and cant get it up on the pad.... engine is a 86 gt 150 johnson.... it has a 22p 14.5 raker prop that came on the boat when i bought it,, it also has a 6 in jack plate.... motor will only turn 4800 at a top speed of about 48mph... the front will not come up on the boat, spray comes off the side of the boat infront of the drivers seat... i have tried the jack plate in several positions and all are about the same out come.. no pad ride at full throttle... and as low as 4200 rpm.... boat also came with a 25p 13.25 shooter 4 blade prop,,, i know nothing about 4 blades,, that i havent tried,,, any one have a suggestion for a prop that will get this boat moving... i figure that the boat shouldnt have any problems doing 60mph if turning the 5500rpms that is recomended...

thanks

 

[Dhadley]

Re: frustrated johnson owner

Have the carbs been disassembled and cleaned? Is the throttle linkage going to full wide open position? What's the timing set to at wot?

 

[steelespike]

Re: frustrated johnson owner

If your getting 48 and you can't get the nose up you may have a hook in the bottom
probably near the treansom.Hold a straight edge along the keel look for a concave section.
Either the bottom is weak or when someone repaired the bottom they didn't get it right.
Is/was the floor spongy?

 

[torbjorn]

Re: frustrated johnson owner

As Steelepike wrote, first question is: is the bottom hooked or straight. If it's become hooked sitting on a trailer with incorrect support (rockers not long enough, pad sits on rollers) then forget trying to get the boat to run dry.

4800 RPM is too little, if the bottom's straight then try a lower pitched Mercury chopper. Nr. of blades is irrelevant, three blades are enough. The motor should turn upwards of 6000 RPM.