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Author Topic:   Lack of top end.
whaler22 posted 07-16-2004 01:59 PM ET (US)   Profile for whaler22   Send Email to whaler22  
This is Long but your help is appreciated....
Last fall I noticed my oil tank for my VRO was leaking. There had been some discussion on the forum about pro's and cons for keeping/loosing the system. I decided to try a few tanks without the vro system and disconnected the input hose to the outboard and plugged and capped the input. I mixed my fuel at 50:1 and pressed on.
I may be fighting an old engine here, but is there anything else I should do. My Top end performance is dropping off drastically. Low and mid range is smooth but seems slow to accelerate to speed. This boat used to be quick. With the VRO, I could turn 5200 rpms/45 mph at WOT. Then it slowly dropped to 4500 rpms and now I'm down to 3900-4200 rpms/32mph max throttle. If the engine is out of gear I can turn 5200RPms. This seems to happen only under load. Could I be sucking air through the oil-side of the system that has been disconnected.
Nothing else has changed as far as linkages, carb butterflys are proper position for WOT, etc.
The motor is a 1986 Johnson 175 V6. My compressions seem weak but I live at 4300ft elv. Current readings are in upper 80's to low 90's. This seems low, a local mechanic agreed but they are even. I don't think compressions changed alot over one winter storage. I didn't take them prior to the removal.

I'm looking for input,(I'll probably get a clean gas can and reconnect another temp oil reservior to check things out. I'm just curious if I miss understood previous post on disconnecting the VRO. Those that have don't mention any performance issues. I may be looking at a tired engine. (COME ON ETEC 225!!!) Give me an excuse to repower!!!
Thanks for input. There are plenty of discussion on pro/cons, I'm looking for more input regarding lack of performance. Maybe I have other issues with this motor not VRO related.

greyg8r posted 07-18-2004 11:48 PM ET (US)     Profile for greyg8r    

Your question might be a little too engine specific for this forum. You might wanto to post this on an engine-dominated forum, like They have model-specific forums for performance issues like yours and there are numerous outboard mechanics lurking to address questions like yours.

IMHO, compression in the 80's and 90's sucks, regardless of how similar. I would should a couple of cans of aerosol de-carb and re-test the compression.

Good luck and let us know what happens.


BMack posted 07-19-2004 04:54 PM ET (US)     Profile for BMack  Send Email to BMack     
Sounds like have a problem. 5200RPMs out of gear! Is that what you meant to say?

Does the engine run smoothly? Check / clean the plugs, check your lower unit and prop hub. Fuel lines, etc.

LHG posted 07-19-2004 05:29 PM ET (US)     Profile for LHG    
Sounds like you should take it in for service. I doubt if anyone is going to be able to "armchair" diagnose your situation.
whaler22 posted 07-19-2004 11:28 PM ET (US)     Profile for whaler22  Send Email to whaler22     
Thanks for the input guys. I'll try the forum mentioned. I'm affraid this old engine is just getting tired. What I ment by "out of gear" was in neutral I can rev it to max rpms. When "in gear",forward, I can only get 38-4200 rpms. I was just hoping maybe I missed something simple.
Anyone hear about the prices of the Etecs yet?

Thanks again,

ratherwhalering posted 07-20-2004 05:23 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering     
ratherwhalering posted 07-20-2004 05:24 PM ET (US)     Profile for ratherwhalering  Send Email to ratherwhalering
Peter posted 07-20-2004 07:37 PM ET (US)     Profile for Peter  Send Email to Peter     
I'll bet you have an air leak through the VRO pump. Don't run the engine at WOT until you confirm that you don't have an air leak in the fuel/oil delivery system! The consequences of doing so could be a fried piston.

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