140 1985 VRO- max RPM 2500 @ WOT

Ran fine last year. Replaced rectifier during off season. Cleaned up old wiring that had no purpose
(boat is a 1977- so when they replaced the engine to my present 1985- they cut wires and just
left birds nests of wire EVERYWHERE- actually had wires connected to the battery that led to nowhere- both hot and ground..... God only knows how it never started a fire!) Anyway, took the
boat out today to test her- ran smooth at low speed but would not go past 2500 RPM @ WOT.
Only blunder was when I winterized the boat, I added stabilizer for approx. 3 gallons of gas-which
was represented on my gas gauge. Little did I know that the wire from the sender to the gauge
was faulty. A new re-run(as part of my wire replacement) showed the tank to be 1/4 full- equivalent of 8-9 gallons of fuel, as I have a 36 gallon tank. I did fill to tank prior to launching the boat- so todays test was on a full tank. Perhaps the hi speed jets got gummed???. If I stay in neutral and rev the engine manually by pulling the arm on the engine - it goes well past 4000+
Interestingly it will sometimes die when I release the arm and returns to idle RPM's.
Any suggestions?? Thanks.

Sal

Re: 140 1985 VRO- max RPM 2500 @ WOT

When you ran it at 2500rpm how did sound? was it crisp or was it lugging? Next time out verify if you were at WOT, possible it wasn't wot. If you thought it was poor gas, take airbox off, loosen the carb drain plugs and let the old gas out, disconnect the fuel line from VRO and purge the old gas.

I think you might a cylinder not firing, run the motor and test the cylinder temps and see if its running on all cylinders.

Whats your idle rpm in gear? if a plug not firing, it would idle poor and stall in gear.

I have the same motor, and as long as the factory engine harness to controlls is intact, the other wires would have nothing to do with poor running.

Re: 140 1985 VRO- max RPM 2500 @ WOT

I have the same motor.
Best to start with the basics.
Compression
Spark
Fuel delivery
Spark plug condition.

Post results and go from there.
Check out the top secret files for a lot of important info.

Re: 140 1985 VRO- max RPM 2500 @ WOT

Hi Paw2000 and Kenmyfam
The engine runs fine at idle- low speed both forward and reverse with no stalling.
Does sound a bit muffled @ 2500 RPS- not really crisp. How do I check to see if I am at WOT?? I have never noticed the positioning of WOT on the linkage on the engine so I wouldn't know how to judge. I am leaning to a fuel / carb problem since it does run ok at low speed. Thanks for your input.

Sal

Re: 140 1985 VRO- max RPM 2500 @ WOT

Could well be. Check the pump output, service the carbs and make sure there are no air leaks in the fuel system.
Don't discount ther compression and spark check though. How do the plugs look??

Re: 140 1985 VRO- max RPM 2500 @ WOT

You should not - ever - run that motor to 4000 RPM with no load.

Are you certain that you are not over-propped? What's the pitch and what's the boat?

Re: 140 1985 VRO- max RPM 2500 @ WOT

I will change the plugs- though they didn't look all that bad. Water separator every year.
Prop and pitch fine. I have had this boat for 10 years- engine rebuilt 2004. ALWAYS ran great
after the rebuild. Only changes made was a new regulator/rectifier during off season. Could be the problem with ethanol in gas. Will check compression though bad compression will create stalling at low speed particularly in reverse. Not the case here. I appreciate all your help.

Sal

Re: 140 1985 VRO- max RPM 2500 @ WOT

Ditto on the compression and spark test.
Make sure spark can jump 3/8th inch gap, not a sparkplug gap.
A timing light will show if it drops spark or has a dead cyl.
If the carbs have not been rebuilt they're well over due.

Re: 140 1985 VRO- max RPM 2500 @ WOT

SaltytSal said:

I will change the plugs- though they didn't look all that bad. Water separator every year.
Prop and pitch fine. I have had this boat for 10 years- engine rebuilt 2004. ALWAYS ran great
after the rebuild. Only changes made was a new regulator/rectifier during off season. Could be the problem with ethanol in gas. Will check compression though bad compression will create stalling at low speed particularly in reverse. Not the case here. I appreciate all your help.

Sal

Click to expand...

How old is the gas you are running? If it's from last season and you didn't add treatment it could be a bit stale.

Edit: oops just re-read the first post. I'd clean the carbs out if I were you.