1989 evinrude 175 Crossflow - No power hole shot and low WOT RPM's

[azhunter]

Hello all,
I'm having some trouble with my 175. It seems to run great in the tank but when its on the lake it has no power out of the hole and only hits about 3800-4000 rpm at WOT. When running at WOT, it occasionally will surge up to 4200 but then drops off again. The motor ran great last summer. I found that I had one bad coil and have replaced it but it didn't change anything. All the plugs have been cleaned and I've checked compression on all cylinders. Compression is a bit low but consistent between 75 to 79 psi which is about where it was when I checked it a couple of years ago. I'm not sure if I have a fuel problem or an ignition problem; I've inspected the timing linkage and it all seems to be working as it should and the carbs where rebuilt two seasons ago. Pumping the ball at WOT doesn't change anything.
Coincidentally to the loss of power, the water pressure has dropped to near zero and the engine definately seems to be running hot. The lower unit was just rebuilt during the off season and a new impellor was installed at that time. I was convinced that it may have been installed wrong so yesterday I took it apart and inspected it but everything checks out.
I'm wondering if the problems are related or if I have two seperate issues going on. Any suggestions on where to start? By the way, I replaced the diverter tubes one, maybe two years ago so at least I know that is not part of my cooling issue. Thanks for your time.

 

[slyrzmb]

Re: 1989 evinrude 175 Crossflow - No power hole shot and low WOT RPM's

Somebody with more knowledge can correct me if I'm wrong, but I believe your problems may be related. When the motor starts to overheat, it will drop rpms to help prevent engine damage. However, I believe it is suppose to drop to around 2500rpm, so in your case, it still seems a bit high. Just out of curiosity, when you say "water pressure has dropped to near zero," do you mean there is nothing coming from the pee hole? At any rate, no water pressure is obviously a problem. Somebody with more expertise will need to chime in here...

 

[azhunter]

Re: 1989 evinrude 175 Crossflow - No power hole shot and low WOT RPM's

Somebody with more knowledge can correct me if I'm wrong, but I believe your problems may be related. When the motor starts to overheat, it will drop rpms to help prevent engine damage. However, I believe it is suppose to drop to around 2500rpm, so in your case, it still seems a bit high. Just out of curiosity, when you say "water pressure has dropped to near zero," do you mean there is nothing coming from the pee hole? At any rate, no water pressure is obviously a problem. Somebody with more expertise will need to chime in here...

slyrzmb,
thanks for your response. I still have water coming out of the pee hole but the pressure on the gauge is only registering about 3-4 psi which is obviously low. To add to it, the water coming out of the pee hole is hot and the heads are also hot to the touch.....too hot.

 

[azhunter]

Re: 1989 evinrude 175 Crossflow - No power hole shot and low WOT RPM's

I'm not familiar with the inner workings of the lower unit. Is there any chance something got messed up during the rebuild that could be causing my low water pressure issue?