2004 115 4 stroke need some help

[explorer 542]

I am used to 2 stroke outboards this is my first 4 stroke so I don't know if this is a normal thing or not. When you hit it to get to plan the rpm goes up to 4000 and just stay's there which is not enough to get the boat out of the lake with any speed. Once the boat starts to plan you can start to trim the engine up and then the rpm will start to pick up kind of like a power band. All I can get out of the engine on take of is 3900-4000 rpm and it just feels like it is holding back power if you put any weight in the boat you are 20-30 seconds to get to plan if you get there at all. I have a 15 pitch prop on the boat which revs the engine at 5400 rpm at WOT equals 35 mph which is all fine but man is it gutless out of the hole.

 

[pokman]

Re: 2004 115 4 stroke need some help

What kind of boat is this on? I have same year motor. Rpms should def. got higher out of the hole and climb as you get on plane. 5400 is way to low, you need to run the rpms as near to 6000 as you can get, lugging these motors is bad. Really need a little more info on the setup.

 

[explorer 542]

Re: 2004 115 4 stroke need some help

What kind of boat is this on? I have same year motor. Rpms should def. got higher out of the hole and climb as you get on plane. 5400 is way to low, you need to run the rpms as near to 6000 as you can get, lugging these motors is bad. Really need a little more info on the setup.

Thanks for the reply been looking for someone with same motor. It is on a 2005 19.6 foot Campion Explorer 542 heavy boat 2000 pound without fuel or people. When you hit the throttle for take off it revs up to 3900-4000rpm try's to plan just can't get itself out of the water when it does lift itself out of the lake and you trim the engine up it starts to take off fairly well just seems dead at take off. thinking about changing the prop to a 14 pitch.

 

[pokman]

Re: 2004 115 4 stroke need some help

I dont know to much about campion boats, but I looked at some pics of yours and it looks fairly big. If you can try a lower pitched prop that would probably be your best bet before you look into anything else. The gear ratio on these motors seems to like lower pich props. My boat is a 01 Bayliner 184 and about 1800 lbs dry. I run a 16p to get to 6000 rpms, so you may just need to prop down. Otherwise was the motor checked over, plugs, fuel filters etc...

 

[explorer 542]

Re: 2004 115 4 stroke need some help

I dont know to much about campion boats, but I looked at some pics of yours and it looks fairly big. If you can try a lower pitched prop that would probably be your best bet before you look into anything else. The gear ratio on these motors seems to like lower pich props. My boat is a 01 Bayliner 184 and about 1800 lbs dry. I run a 16p to get to 6000 rpms, so you may just need to prop down. Otherwise was the motor checked over, plugs, fuel filters etc...

I changed plugs last week fuel filter looks fine it is a big boat and I do think a larger engine would help a lot but not in the budget right now so I am going to have to try a smaller prop how much difference does dropping down a prop pitch size make in your rpm?

 

[explorer 542]

Re: 2004 115 4 stroke need some help

also wondering if the change in rpm is in the WOT only or will the rpm pick up at take off to?

 

[pokman]

Re: 2004 115 4 stroke need some help

If you change to lower pitch prop the ball park should be 150-200 rpms for every pitch you drop. A little less for a 4 blade. RPMs should increase across the board when you drop pitch. If I was you and you have a good local prop shop, try a 4 blade 14 and 4 blade 13 pitch prop. 4 blade will give you better hole shot and midrange punch and better control, but you will sacrifice a little top end. Solas and mercury spitfire are well rated 4 blades. I think 13p is where you'll end up.

 

[explorer 542]

Re: 2004 115 4 stroke need some help

Thank you for your help I am ordering a new prop today will let you know what happens I am hoping that it helps with getting this boat to plan cause it is a real dog also hoping it is not a engine problem with it not getting up to planing rpm fast enough. It is just that the engine seems to run fine it just doesn't have enough balls to lift the big pig out of the water when there is a load of people and luggage in the boat.

 

[pokman]

Re: 2004 115 4 stroke need some help

I think it is the prop. 4 strokers dont have the punch out of the hole in the first place(compared to similiar 2 stroke) plus you have a big boat that is slightly under powered. It is a great motor though get her propped right and you should be happy.

 

[explorer 542]

Re: 2004 115 4 stroke need some help

thanks again will keep you posted on what happens with a differant prop should know in a day or two the prop guy has a 13 pitch that he will let me try and if I don't like what happens he will replace it with a 14 pitch keeping my fingers crossed that it helps. This is a new boat to me and it is a great boat for fishing or crusing the lake on a nice day but with more then a couple of people in her she is embarrassing trying to get her to plan.

 

[explorer 542]

Re: 2004 115 4 stroke need some help

Thanks Pokman should have read your reply more carefully earlier after spending to much money at the repair shop to get the boat motor scanned just to be told that everything is fine. I went out and bought a 13 pitch 4 blade prop put the boat back in the water last night she lifts herself out of the lake in under 4 seconds runs about 35 mph at WOT with the rpm's right around 5900. I only had myself and my son with me which is not much weight but the boat performed much better going to load her up this weekend with some weight and hope for the same results. I can tell though that with the rpm's running up higher that the engine is not loading itself up and just seems to be happier.