problems plaining out but its not the prop

[joeblue]

i have a 89 procraft with a 150 evenrude on it when i hammer the throtle down to go it just dosent go sometimes might take me a min to plain once i plain it takes off. i am only running at about 4200 rpm at full throtle so i am sure the prop might not be perfect but it shouldnt be doing that.

sometimes i take it out it will pop right out of the water. i changed all fuel lines plugs wires and coil packs.

next i was going to change power pack.

when i had it in for winterizing guy told me the carbs sounded fine it runs alittle rough but it is 20 years old.

any sugestions on this problem i am lost and tired of thowing parts at it.



thanks

 

[JB]

Re: problems plaining out but its not the prop

Ahoy, Joe.

Welcome to iboats.

If you are only getting 4200rpm at WOT you are very overpropped or running on 5 cylinders and should expect a slow hole shot.

Changing parts is the most used, most expensive and least effective troubleshooting method known to man.

What have you done to prove that all cylinders are making power? What prop do you have on her?

 

[metriccrescentwrench]

Re: problems plaining out but its not the prop

i am lost and tired of thowing parts at it.

Do you have a factory service manual for your engine? If not you should definitely find one. Don't settle for anything other than the OMC factory manual, you can usually find them on ebay, and if not there's a company that sells reprints (can't think of their name off the top of my head, someone on here will know).

That engine should be turning somewhere in the ballpark of 5500 to 5800 rpm at WOT, so somethings not right. Check the easy stuff first. Warm it up on muffs then check compression. Use an inductive timing light to make sure you don't have a miss on any cylinder. Get a spark tester to verify you get a good spark across a 7/16" gap on each cylinder.

 

[joeblue]

Re: problems plaining out but its not the prop

i am running a 13 1/2 by 23 pitch and it is a 17' procraft bassboat. i had all intentions of putting a new prop on when i got the boat out this year. but i have been fishing with my buddy in his boat and the last time we took it out it started doing the same thing my boat is doing. that is what gave me the idea that it was elec.

 

[joeblue]

Re: problems plaining out but its not the prop

i will have the compression tester and inline spark tester this weekend and i will let u know. thanks for the help

 

[emdsapmgr]

Re: problems plaining out but its not the prop

Get and inductive timing light. Put it on each plugwire when the boat is idling in gear at the dock. (under load). The flashes from the gun will tell you if you have good spark, intermittent spark, or weak spark on each wire. If the spark is solid on each, look to the fuel system for the problem.

 

[joeblue]

Re: problems plaining out but its not the prop

this my sound like a stupid question but is there a difference between a timing light u would use for a car and a inductive timing light.

 

[emdsapmgr]

Re: problems plaining out but its not the prop

Same thing. All latest timing lights have an inductive type pickup on the spark plug lead which makes it easy/quick to check each wire by merely clipping the end lead over the plug wire while it's running. The early timing lights had a spring lead insert which had to go between the plug tip and the timing light. Works ok, but just takes more time because you have to shut the engine off each time to move the insert.

 

[joeblue]

Re: problems plaining out but its not the prop

thanks i just never knew it was called inductive just always called it a timing gun