1987 150hp vro runs slow

[Don Dickinson]

Two days ago, i had my recently purchased 1987 boat out for the first time. the engine ran great. top end on the bass boat with 150 envinrude was about 60mph.

yesterday i took it out and it bogged down. top end was about 15mph. the boat wouldn't plane even with the throttle all the way down. if i pressed the choke in while at top speed it would get another couple mph or so.

the fuel was the same as the day before (i added 10fresh gallons to the tank, on top of the previous 5 gallons).

the engine had new plugs installed and was tuned up last year according to the previous owner. the plugs looked new to me.

looking for advice on where to start. i'm mechanically inclined, but don't know much about marine engines. i assume it A) has a fuel system problem or B) isn't running on all 6 cylinders.

any advice appreciated.

thanks
don

 

[angus63]

Re: 1987 150hp vro runs slow

Welcome to the forum!!!!!

First, that 15 gallons is about 1 hour of run time at WOT!!!!
Are you sure you have enough fuel???

Try a remote tank full of fresh fuel and see if the problem continues.

Let us know....

Good luck

 

[jmerc]

Re: 1987 150hp vro runs slow

Don, I had a similar problem with my Johnson 150 and also assumed it was a fule problem. I changed the water seperator filter first then the inline filter, still ran the same so I drained the gas tank and still had same problem. Next step was to change the tank pickup and the fule lines from the tank to the motor and still had the same problem. At that point it was time to call the mechanic. He tested compression and that was all good then he did some more tests and found I wasnt getting any spark to one side of the motor. He did a few more tests and finally found the problem to be the Stator. Replaced it and Im running like a offshore racer now. Boat is running better then ever. To bad I didnt call him before I took the 38 gallons of fule to a disposal but you know how that goes. Thats why they call it a B.O.A.T. Break Out Another Thousand. Hope this bit of info helps you.

 

[tashasdaddy]

Re: 1987 150hp vro runs slow

Welcome to iboats, Don. start with the basic troubleshooting. check, compression, spark, and fuel flow. it could be any number of things. as mentioned above. dirty carbs, bad coil, power pack, clogged vent on fuel tank, dirty pick up screen in tank. fuel water separtor, or just an air leak. here are some electrical test you can perform C&P w/o " "http://www.boatpartstore.com/page33.asp" several pages. it could even be a bad control cable, not moving the linkage,

 

[hawkf250]

Re: 1987 150hp vro runs slow

my jonny 150 had the same symptoms, rebuilt the carbs and im running great, hitting the choke did the same in mine as well.

 

[Don Dickinson]

Re: 1987 150hp vro runs slow

thanks for all the advice.

an update ...
changing to a remote gas tank didn't fix it.

i found an un-done connector in the engine and reconnected it ... turned out to be the VRO warning. since VRO is disabled, turning it on just caused an alarm sound every few minutes

the carbs were rebuilt last year and the engine had a tuneup last year too. i will take the carbs apart and make sure i don't see anything bad in there, but i suspect they're ok.

the previous owner did replace a powerpack last year. he said that the engine was behaving as it is now ... he said it was running on 3 cylinders because one of the powerpacks went bad.

perhaps he didn't install the powerpack correctly ... loose wire or something? not sure. if i can find the powerpack, i'll check it out and see if something jumps out at me. i'll dig around the forums and try to find instructions for testing a powerpack.

Question: i assume if i take the boat out and start pulling spark plugs i should notice power going down. if i pull one side of plugs and there's no change, is it likely i have a bad powerpack on that side? haven't done it yet, but i'm thinking that's a good thing to try.

thanks!
don

 

[angus63]

Re: 1987 150hp vro runs slow

Does your '87 have a shift switch? Check where the remote cable attaches to the shift arm on the motor. Disconnect the switch and try again. If misadjusted, the switch knocks out 3 cyls during shifting.
Also I believe on that motor you can simply swap powerpacks to see if the problem follows the pack.
Good luck

 

[Don Dickinson]

Re: 1987 150hp vro runs slow

i've found a couple other things ...

1. the remote cable seems ok.

2. it is probably noteworthy that my tach doesn't work. this leads me to think a rectifier might be an bad ... from my reading i've heard that can cause problems with the powerpacks. not sure why it would kill one powerpack and not the other, but ...

so, my next step is to:

1. hookup the water muffs and check all the plugs for spark
2. assuming i'm missing spark on 1/2 of the engine, i'll clean the battery terminals, test and replace the rectifier as necessary, and then the powerpack that's bad.

sound like a plan? all of this assumes that i find the engine not firing on one side because of the power pack.

tia,
don

 

[Don Dickinson]

Re: 1987 150hp vro runs slow

just an update or those who care ...

1. i fixed the tach ... wire was lose

2. its running on 3 cyliners. i haven't tried swapping the powerpacks to see if it the problem follows the packs, but i have to tow it a few miles to get it in the water to test it. i'm guess its the powerpack.

3. i ordered a powerpack from iboats.com

4. i think that will fix it we'll see on Wed when the part arrives.

5. thanks for all the advice and help.

 

[evinrudexp]

Re: 1987 150hp vro runs slow

Hi, im having similar issues with my 88' 150hp evinrude. Was it the power pack???