225 Johnson Top End

[Raw Seas]

I'm having problems with my 97 225 Johnson, can not get RPM's over 4500. Two years ago replace the lower unit with a new one and it ran and sounded great, performing as it should. Recently oil pump broke down and I had to replace the powerhead. After the break-in period gave it the gas and it wouldn't reach top end. Pushing a 26 WA with fuel and guests, I have problems planing. Changed props with similar results. Mechanic shop tested engine and said it's operating correctly. Sounds and looks fine, high RPM's in neutral, but not in open water. Changed oil in lower unit and it looked fine. Asking for my next move..TY

 

[Br1dgemann]

Re: 225 Johnson Top End

This may be a stupid question, but was the powerhead replacement done as a complete unit or did your mechanic get a short block and swap over all your components ie: the carbs, throttle bodies, stator, power pack, yada yada. If it was done as a complete assembly, maybe you got a 200 powerhead instead of a 225. I realize the cubic inch displacement of both powerheads would be the same, but the carbs and throttle bodies are different. Whether the horsepower difference would be enough to give you the lack of performance you describe is another topic of discussion.

 

[Raw Seas]

Re: 225 Johnson Top End

Good Guess - But it was a short block swap

 

[Br1dgemann]

Re: 225 Johnson Top End

First place I would look then would be to verify the throttle cable is opening the carb's butterfies. With engine not running, push the control to WOT. Remove engine cover and the silencer in front of the carbs and look down the carb throats. The butterflies should be perpendicular. If they are not, sounds like your cable needs adjustment.

 

[Saki1211]

Re: 225 Johnson Top End

I've got a 2000 225 Johnson HO that had this same exact problem. I could barely get my 20ft Javelin Renegade on plane and when I did finally get it on plane I could only manage 45-50 MPH out of it. It took 3 trips to the shop for them to figure out what it was. My timing base would work fine when in the shop but it would drop a cylinder everytime I took it out and got on the motor. On the 3rd trip it finally dropped the #1 cylinder in the shop and we replaced it. I haven't had the first problem with it since I got it back. I will say this, be careful if it is dropping a cylinder. You can seriously mess up your motor if your not careful.

 

[Br1dgemann]

Re: 225 Johnson Top End

Raw Seas,

Any progress on your problem??

 

[CDBritt]

Re: 225 Johnson Top End

Same problem. 98 Johnson 225 venom, lower unit rebuilt last month and it won't go over 5000 rpms WOT. Adjusted throttle, cleaned all six carbs, new plugs, and fresh gas, still nothing. Last year I was running 6000 rpm's at 73 mph. This year 5000 rpm's at 50 mph. 20' stratos

 

[daselbee]

Re: 225 Johnson Top End

Bridge this sounds like our problem. Seems to be the same stuff we are experiencing.
My transom is nearly repaired. On the water soon.

 

[Br1dgemann]

Re: 225 Johnson Top End

Bridge this sounds like our problem. Seems to be the same stuff we are experiencing.
My transom is nearly repaired. On the water soon.

Look forward to working on this further, Daselbee