How many HP actaully is my Mercruiser? Prop pitch question?

[Gotta Bite]

I bought my current boat used a few years ago. It's a 1987 Sea Sprite with a 4.3L Mercruiser Alpha one. I never got a manual with it. Someone asked me a few weeks ago how many HP it was. I was not sure. I went to the Mercury Marine website and they had various listing for HP for that motor. I believe it started at 150 and went to 220. I called their customer service a few days ago waited so long I had to leave a message and I still did not receive a call back yet. My other question is what's the best pitch for an all around prop. I use the big engine to troll also so I don't think I want something that won't let me keep the boat speed down. What would suit me best for trolling and getting me up on plane fairly quickly? Your feed back is appreciated.

[Jack]

Hi !

I believe if you have a 2 barrel carb it's probably 150hp if you have a 4 barrel carb 220hp. As far as prop goes I would get one that lets the motor run in it's max rpm range at wot . If it won't troll down enough try some trolling bags. Good Luck !

JT

[Gotta Bite]

I see where there is also a 190hp in the 4.3L . It runs great and no complaints, just wondering what the HP is. My last boat had an outboard that was 85HP. This motor does not show or state what HP.

[ray koziatek]

im suprised the id plate on the engine doesnt have the info (if there is a plate) both of the 4 cyc ive had ,were marked with all the info pertaining to that engine.I dont belive there is a pitch per horsepower way to figure out what prop to use ..its more rpm to weight ratio , heres a example my 120 hp with 1 or two people in my 22 ft alum w 4riggers (20lb ea)5 10lb balls,1 kicker bout 100lbs,36 gal fuel about 200lbs,100lbs tackle,and safty equiptment, 50 lb cooler...will go 30 mph at max rpm 4300 ,BUT throw in MUSKY AND JASON another 500 lbs and it struggles to get on plane in smooth water and forget getting up if there are 2 ftrs.. (17 pitch prop) .after going with the recomended 15 pitch prop from Hanky (L&M) with the lighter load (2) people it pops on plane much faster but will only do 26mph at 4300 rpm with plenty of throttle left to go but i dont want to exceed (blow up)mfg recomended rpm"s. with 4 people it still gets on plane very fast still doing 26 with plenty of throttle to go... here is a general rule of thumb i learend in the 80tys when i was doing the Jet Ski thing... 1 deg pitch =2mph loss or gain thus i lost 4 mph by going with smaller pitch at 4300rpm..,also 1 deg of pitch =200 rpm change .....thats why i have more throttle to go after reaching 4300 rpm,,, So when i got the big boys (musky,jason)on board for the derbys ill run the 15 deg pitch,if im running a lighter crew(me) then i will stck the 17 deg pitch so i can feel the rush of 30 mph wind in my hair (both of them)and my back, and get off shore to the secret (buffy grounds) fishing spots quicker..

[Jack]

From what I remeber the early 4.3's were a 175hp then I believe around the early 90's they started rating hp at the prop and it went to 150hp with 2 bbl carb. Seems like the newer 4.3 is 190 hp . I have had 3 of them over the years in differant boats and have never been disappointed in the hole shot. The 4.3 is a chevy 350 with 2 cylinders cut off and has a lot of low end torque. I would run it with the prop that gets you to the max rpm range . I have had the boats loaded with people and always planned off with no trouble.

try this link http://www.perfprotech.com/store/articl ... tions.aspx

[Gotta Bite]

I'll have to check and see if there is an ID plate on the motor when I am up next weekend. Maybe I'll just ask Mike at the Marina he may know since he works on them daily. Thanks for the feed back.