90 horse prop

[tvpear12]

I have a 1992 90 horse v-4 crossflow with a 13x19 prop. i have been told ro go to a 17 pitch prop. should i go 13x17 or 14x17? does anyone know what size came on this engine from the factory? I have to run my engine way down on the tilt to keep a good bite or it seems to cavitate as i start to tilt up. engine is sitting on the transom as low as it will go. The reason i feel that its cavitating is just as the bow of the boat starts to come down and on plane it sounds like its slipping. i can trim down and it will then bite. any suggestions would be welcome. thanks, Ted.

 

[WillyBWright]

Re: 90 horse prop

If you increase diameter, you'll ventilate easier. Add 1" of diameter and 1/2" is sticking further up, and that extra 1/2" will be more likely to grab some air. Sounds like you just have to keep your thumb on the trim button. For cornering or rough water, that is not at all unusual. You should always start from still with the motor fully trimmed in, then trim out once it planes. If you start from still with the motor at the angle it ran best on plane, you'll ventilate every time. That's why the trim switch is put in such a convenient place.

 

[Solittle]

Re: 90 horse prop

You motor may not be mounted in the right place. Where is the cavitation plate relative to the bottom of the hull? To start with it should be even or up to 1" above the bottom. <br /><br />Get the motor set right then go for the prop.

 

[shebe3]

Re: 90 horse prop

I think solittle has the solution. I doubt if your cavitating, your ventalating- drawing air, which means you have to lower the prop or remove obstructions from in front of the lower unit on the boat bottom.

 

[tvpear12]

Re: 90 horse prop

How do you remove abstructions? there is nothing on the bottom of the boat to remove. would a jack plate help in this case? to move the engine back. I cant lower the prop , because it is setting all the way down on the transom now. I think its because the back of the boat is inset where the drains are causing the water to be disturbed before it gets to the prop. what do you think i need to do? the boat is a 1989 tracker glass hull 1600TF Tournament series.

 

[Solittle]

Re: 90 horse prop

You wrote "what do you think i need to do? "<br /><br />Did you read my last post????? Let us know & then maybe we can help.

 

[tvpear12]

Re: 90 horse prop

I am asking if that should be done with a jack plate? the engine is as low as it will go.The cavitation plate is about 2.5 to 3" above the bottom of the boat where the livewell drains are witch is set back from the bottom of the transom.you do mean from the bottom of the boat and not the transom dont you? I know realize that the engine needs to pretty much be lowered. just need to know what method to use to lower it.

 

[ddaigle]

Re: 90 horse prop

Willybwright, seems to have hit the nail on the head. You always have to start off with the motor all the way down and not start trimming up until you are fully on plane. You said it bites if you trim it down so keep it trimmed down unless your planing and dont worry about your motor height if it bites when its trimmed correctly.

 

[tvpear12]

Re: 90 horse prop

I heard that running tilt down while on plane is hard on the engine. i never tilt up untill i am on plane this is where the ventalation comes in. now lets review my earlyer post and in them you will find the type of boat this engine is sitting on. i would rather set the engine in the right place.i would not say it is correctly trimed when on plane and the trim is almost all the way down, would you? i stated in the earlier post where the cavitation plate is in relation to the bottom of the hull and you still say to leave it alone. well i cant get the rpms up like everyone says to do with this engine trimmed down. i am very aware that i should wait untill the boat is on plane before tilting up, and thats what i do. the cavitation plate is setting to high in relation to the bottom of the hull. once again how do i get the engine lower? I am kinda dumb to set up but i do know how to drive a boat, and i do know when somthing dont feel or sound right. This engine sounds like it is catching air. I think that the bottom of the boat is disturbing the water before the prop.