boat will not plane off will not run over 2500 rpm please help

[jodylee289]

I have a 1987 procraft with 110 hp evinrude vro oil injected. What the boat does it will plane off some time but not all of the time. I have done a compression check on all four cylinders and the compression is about niney to ninety five on all four cylinders. I have read many threads saying that it could be in slow mode, but i dont have any alarm. possibly bad alarm horn. I have disconected both of the temperture sending units and the boat still does not run right Are there four or two of these sending units? I have sprayed carb cleaner in both carbs and even ran stp in my boat. Still no luck. Sometime the boat will plane off other times it wont. it is a very intermintent problem. I am confused it seems to want to run when there is no load on the engine When i turn the wheel all the way to the left or right the engine will rev up from a dead stop because there is little load on the motor then. Any help or suggestions would be helpful. I manage a automotive service department for pep boys, and excell at cars, but this boat motor has got me puzzled

thanks jody
jodylee289@msn.com

 

[Gary H NC]

Re: boat will not plane off will not run over 2500 rpm please help

Welcome to Iboats,
First of all using all caps is not necessary.Some people consider it yelling.

Second,post exactly what Engine make,year,model you have you will get much better advice.

I hope its not an outboard you are revving like that under no load

 

[jodylee289]

Re: boat will not plane off will not run over 2500 rpm please help

1987 Evinrude 110 hp with vro oil injection

 

[ob]

Re: boat will not plane off will not run over 2500 rpm please help

Your 87' model isn't equipped with the s.l.o.w. feature.There could be several possibilities that is causing your symptom to include wrong prop application,restricted carburetor passages, throttle linkage not allowing full opening of carb flaps,or loss of spark to one or more cylinders.Need more info to assist in narrowing down your problem.What is the length and approx weight of boat this engine is pushing?Which prop dia and pitch are you currently running?Insure that when the throttle is advanced to wide open position that the carburetor flaps are opening fully horizontal.Did this rig set out of use for an extended period?If so,my money is on restricted fouled carburetors.

 

[Quick-man]

Re: boat will not plane off will not run over 2500 rpm please help

I agree with ob, it sounds like dirty carbs, you can check spark with a spark tester, I am sure you have one at Pep Boys. Unfortunately just spraying carb cleaner in the throats will not clean out the carbs and running a carb cleaner may help but will not clean them properly. Do you know how long the engine sat? When the carbs were cleaned last? I know AutoZone (sorry) has a 1 gallon can of ChemDip that is used to soak the carbs. Remember to take out all orifices, also all plastic bits or they will be gone when you take the carbs out of the bath. Follow up with a can of carb cleaner and blow out the passages with compressed air.
High Speed jets are in the bottom of the bowl, so is left over gas that sits there, my carbs were so bad I thought someone put tar in there. The ChemDip cleaned them right up.

 

[jodylee289]

Re: boat will not plane off will not run over 2500 rpm please help

Ignition is not a problem, strong 1/2inch spark. I think it is carb problems, I saw where you can buy rebuild kits for about twenty dollars a carb. That is very affordable. The type of craft that it is pushing is a sixteen foot procraft. The boat sat for about 4 years, the pervious owner did not want to fix the boat because he got a new one. The thing that leads me to beleive that it is not a carb, is when i was inspcting the throtle linkage, the butterflies open wide, and the motor will rev up with no load on it. that is the key to solving my problem , motor will not rev up with load.When i bought the boat it did not run and now i got it to this point. To answer the question about props, i dont know anything about the prop. I dont know how to measure pitch or anything, I am assuming it is stamped on there.

 

[tashasdaddy]

Re: boat will not plane off will not run over 2500 rpm please help

if the boat sat for 4 years, immediately change the impeller, and clean the carbs, including the high speed jets, which requires a special tool to get out. you can see complete diagrams at BRP-evinrude.com literature, engine diagram. special tool can be bought at dealer, or made from a quality screwdriver: http://i155.photobucket.com/albums/s311/frankr_photos/FixedJetScrewdriver2.jpg?t=1177353186

info you should have had before starting: http://forums.iboats.com/showthread.php?t=158086

 

[Striper500]

Re: boat will not plane off will not run over 2500 rpm please help

I want to let you know that this winter I recently purchased a boat with the same problem. I checked everything from the coils, power pack, stator, plugs, plug wires, fuel ball, separator etc. The boat would rev well in excess of 4,000 w/o a load. It wasn't until 20 hours + of time spent did I finally break down to take the boat to my local mechanic by water. It was approximately a half hour by water at that speed (2500 rpms) only for him to tell me that he couldn't figure it out. On the way back home, don't you know the boat took off. I have put approximately 100 hours on it since. I am assuming it was a restriction in a carb. Not saying that you will get that lucky, but I believe that where your problem may be. If you rebuild them yourself, Be VERY VERY careful and read about how to properly adjust all of the jets. If you run a cylinder lean, it can cause damage. Good Luck - Chris