1998 johnson 225 looper new rebuild

[dirtstyle52]

On a rebuilt engine with less than 10 minutes run time @ 1500 RPMS (per manual) all the cylinders range from 95 to 105psi and one hole has 85psi. I pulled the head off and looked at the cylinder, hone marks still look great no scaring what so ever...should I finish the break in or should I pull the piston and check the rings?

[davemvegas]

On a rebuilt engine with less than 10 minutes run time @ 1500 RPMS (per manual) all the cylinders range from 95 to 105psi and one hole has 85psi. I pulled the head off and looked at the cylinder, hone marks still look great no scaring what so ever...should I finish the break in or should I pull the piston and check the rings?

i have found that the small end of the looper rods tend to bend. i had a rod with a slight bend on wrist pin end of rod. only sign was piston was down in block about .015 and that was 15psi on the gauge. i thought i might have bought a piston that was machined wrong. but after laying the rod on a flat surface i could see a slight bend. then ckecking thru what i thought was good spares i found 2 of them with a slight bend.when i replaced the rod piston came to top of deck like the rest. 100psi is what i get for compression with stock heads and open idle releifs.

[dirtstyle52]

Thanks for the info....tomorrow I will try and put some time on the engine and I will repost findings

[baja200merk]

Was did you replace the rod on the cyl that was previously blown?

I pulled this rod out of a 98 with low hours, no evidence of water and the cyl/piston showed no signs of wear but the motor would not make a complete rotation due to the bent rod hitting the rod slot. Older guy I bought it from said it just shut off and wouldnt start.