new engine

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fishbonejr

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i have a 1989 v20 steplift with a new 225 h/p jasper i/o that i am not very happy with because it does not preform as well as my origanal merc 165 h/p i/o i used to get about 42 m.p.h. with the old engine but now with just 2 people i can get max 31 m.p.h the old one through a rod and cracked the block one day or else i would have kept it. i did not choose this engine my mechanic said was a great engine and to trust him. It is a reliable engine but not a powerful engine. is somthing wrong with the engine or is there a way to get more power out of the engine.

p.s. this is my first time posting
 
You sure about that 41 mph? Best I've ever done is about 36. Anything else change? prop? outdrive? are you getting max rpm's
 
Jasper has a pretty good warranty if I'm not mistaken...If you feel like you're gettin' the straight scoop from your mechanic, have him check out the motor thoroughly, including compression testing all cylinders...If you feel the need, take it to another mechanic and have him test same (or you can get your own compression gauge and bone-up on how to test)...w/more HP, there also may be a need to change props, but to tell you the truth, you'll have to get that from someone more knowlegeable of I/O drives...

You're postin' speed comparisons, but are you gettin' the same, better or worse RPMs from the new motor as the old?...
 
I REBUILT MY 470 AND ON FLAT WATER 45 MPH 2 MEN AND GEAR AND A 3/4 FUEL. SLOWER IN A CHOP OUT ON THE OCEAN 35-40 MPH THATS WHAT MY GARMIN GPS SAYS IM DOING BUT I LIKE TO RUN ABOUT 30 MPH SMOOTH AS CAN BE
 
my r.p.m. would top out a 4500 with the merc but now i am lucky to get 3800 (i am not sure about the max rpm on the jasper) and when ever i do the temp rises from 155 (which is how hot my old engine would get at top speed) to about 190 F. i have never changed the prop with the new engine i changed it about 2 years ago with the old engine. I dont know if this makes any difference but the lower unit has about a 4 inch crach in it that i noticed after the new engine was installed would this make any preformance differences. i would use another mechanic but i keep my boat a a marina and they are right at the marina and because of that they are much cheeper for labor other wise i would have had sombody else replace my engine. My g.p.s. said 36 knots i think if my math is correct that should be 41 42 mph.
 
I had a 165 I/O years ago in an old v-20 and I was lucky to get 30 mph on a flat day with two guys and I thought that was about par for that engine and weight combination.... Frank
 
fishbone, find out what max rpm for your new motor is as recommended by Jasper...that's what you're shootin' for when "proppin" your motor...

...a 4'' crack in your lower-unit could be VERY signifigant...do what you gotta(repair or replace) on that issue and while you're at it, you probably wanna put new water-pump in it...

You may also need a thermostat that allows more water flow, too...
 
i dont know much about io,s but, i would have to agree with rap. you gotta get that crack checked out. it might be why you lost ur first motor!
 
I also had the 165 I/O on my boat, toped out low 30's and went nice mid 20's

Converted to O/B 175 hp and go's nice low 30's and top out low 40's

You need tac, to make sure you are proped right.

After you get tac you will be able to see if you are even getting full throttle??
 
well it looks like i am going to replace the lower unit and have a new water pump put in. then i will check on the prop and the thermostat. they told me to wait on the engine after i did all this to see if that fixes the preformance issues.

thanks everybody
 
msbhammer said:
Post Pics of te boat, engine and CRACK !! ;D
Click to expand...


ok i am taking the boat ou this weekend so i will have the marina guys put it on a workrack and take some pictures.
 
Let me ask you something?

When you went from the 165 to the 225, did you change the gear ratio in the outdrive??

I had a 165 and got a outdrive from a 220 and the gear ratio is totaly different!!
I had the out drive rebuilt to match the motor.

Just a thought?
 
no i did not change any thing with the out drive. but i took it out today and got standed :'( i think that there is a major engine problem now because i could not go above 800 rpm with out it cutting out it took about 30 seconds for it to get on plane and i was not even geting 24 knots with two people onboard in front i think that there was somthing wrong with the engine when i had it installed and now it is showing. after i got on plane it sputtered and my wheel would jerk to the port side of the boat but i didn't hit any thing then it would not let me go above 800 rpm. i will have the mechanic look at it tomarrow and we will go from there.
 
Good Luck Fish, just so you know I had a redone and beefed up Chevy Blazer that I used as a tow/hunting/off roading vehicle and I replaced the stock 305 CI with a 350 from Jasper- one problem after another, rear main seals engine bearings, cam problems etc etc. They replaced the engine three times at their expence with new engines. Supposed to have been there top level re-man. CRAP
Finally after third engine had problems I had them pull it and I bought a 350 from a junk yard with 60,000 on it and drove it all over no problem.
I hope they have gotten better and it is a simple fix for you but watch them, they will stand behind it on while on warranty but theie quality control is CRAP
 
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