Hello Everyone,
I am up against a recurring issue and am hoping that someone more experienced than myself can help me resolve. I bought a 1983 Ranger Bass boat 8 years ago. It is powered by a 1983 Johnson TLCRD 115 hp V4. I knew going into it that the #3 piston had low compression (50 p.s.i.). I have rebuilt a bunch of various motors ranging from lawnmowers, snowmobiles and V8's with success, so I figured I would give this boat a shot as the price was right. I removed the power head and had machine shop bore the cylinders .040 over. Installed new .040 over Wiseco pistons, rings, wrist pins and wrist pin bearings. I noticed the original crank shaft had some pitting due to corrosion from sitting for long periods. I found a used crank and had the machinist look it over and it passed. Rod and Crank bearing looked excellent so I re-used them. Of course all new gaskets and sealants for the assembly. I cleaned and rebuilt both carburetors. This motor ran great for about 4 years of heavy usage. I used the VRO as fuel pump only and would premix the fuel 50:1. Always used the Evinrude/Johnson XD30 and always treated with Fuel Ox marine. I would take compression readings every spring and all cylinders were at 113 to 116 p.s.i. During the summer I noticed a drop in power and decided to perform a compression check. Unfortunately the starboard #3 cylinder was lower than the others (75 p.s.i.) I looked in the the piston chamber and saw damage to the cylinder walls and top of piston. I had lost another ring and had to once again remove the power head and this time had to have a new sleeve installed and performed the same procedure as before. I did some research and changed a couple things to hopefully fix the problem. I changed the spark plugs from electrode to surface gap because I run at WOT a lot. Also noticed my timing was advanced a little at full power (32 BTDC) and adjusted to (28 BTDC) as noted in the manual. Fast forward to present and the same issue yet again. Damage to the #1 and #3 cylinder walls and pistons. I am thinking that maybe those cylinders are running too lean and causing this issue, but I am not sure. Factory reeds seem good and I have cleaned and rebuilt carbs every two years. #1 & #3 pistons definitely look like the mixture is leaner than the #2 & #4 pistons as there is burnt oil on top of the #1 & #3 and the fuel wash is way smaller on the intake port side of pistons. If anyone has had a similar issue and can share possible solution.
I am up against a recurring issue and am hoping that someone more experienced than myself can help me resolve. I bought a 1983 Ranger Bass boat 8 years ago. It is powered by a 1983 Johnson TLCRD 115 hp V4. I knew going into it that the #3 piston had low compression (50 p.s.i.). I have rebuilt a bunch of various motors ranging from lawnmowers, snowmobiles and V8's with success, so I figured I would give this boat a shot as the price was right. I removed the power head and had machine shop bore the cylinders .040 over. Installed new .040 over Wiseco pistons, rings, wrist pins and wrist pin bearings. I noticed the original crank shaft had some pitting due to corrosion from sitting for long periods. I found a used crank and had the machinist look it over and it passed. Rod and Crank bearing looked excellent so I re-used them. Of course all new gaskets and sealants for the assembly. I cleaned and rebuilt both carburetors. This motor ran great for about 4 years of heavy usage. I used the VRO as fuel pump only and would premix the fuel 50:1. Always used the Evinrude/Johnson XD30 and always treated with Fuel Ox marine. I would take compression readings every spring and all cylinders were at 113 to 116 p.s.i. During the summer I noticed a drop in power and decided to perform a compression check. Unfortunately the starboard #3 cylinder was lower than the others (75 p.s.i.) I looked in the the piston chamber and saw damage to the cylinder walls and top of piston. I had lost another ring and had to once again remove the power head and this time had to have a new sleeve installed and performed the same procedure as before. I did some research and changed a couple things to hopefully fix the problem. I changed the spark plugs from electrode to surface gap because I run at WOT a lot. Also noticed my timing was advanced a little at full power (32 BTDC) and adjusted to (28 BTDC) as noted in the manual. Fast forward to present and the same issue yet again. Damage to the #1 and #3 cylinder walls and pistons. I am thinking that maybe those cylinders are running too lean and causing this issue, but I am not sure. Factory reeds seem good and I have cleaned and rebuilt carbs every two years. #1 & #3 pistons definitely look like the mixture is leaner than the #2 & #4 pistons as there is burnt oil on top of the #1 & #3 and the fuel wash is way smaller on the intake port side of pistons. If anyone has had a similar issue and can share possible solution.