Got new motor in from rapido took it out and it will not plane or get past 3000 rpm

jrturbo · Jul 24, 2011

PLEASE HELP!!! Got new motor in from rapido took it out and it will not plane or get past 3000 rpm but it will rev past 5000 rpm out of gear.. What the is my problem.

Bt Doctur · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

was the new motor adjusted and broken in properly, timing and carb normal?

Don S · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

but it will rev past 5000 rpm out of gear..

Don't do that,that is a meaningless test. You can go well over 5000 rpm with all the plug wires off one side with out a load.

You can have the best long block in the world installed, but if you have intake manifold leaks, carb/manifold leaks, carb problems, plugged up fuel system, ignition problems, (timing, advance etc), it's not going to run.

Have you done a long block replacement before? Did you have the OEM service manual and follow it?

jrturbo · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

what do you mean adjusted properly the carb should b fine it was last year just a bad motor and wrong cam. I was trying to break it in.. I timing was set 8 deg. No I have never dona long block before this is my first boat got it last year not knowing an thing about boats and got it home found out someone pu a truck engine in it most likly out of a wrecking yard took it out 3 time woud not get over 3500 rpm and then it spun a bearing, so know I got this engine from rapido and put it in and it is lacking power. it feel like it has too much wight but I know that is not it.

180shabah · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

So the old engine wouldn't reach proper WOT either?

What boat?
weight?
gear ratio?
prop?
Then add in all of the possible engine issues...

jrturbo · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

No it would get up to 4200 rpm wot it just was n old truck engine with the wrong cam. The boat is a 1987 19' celebrity with an Alpha 1 ratio 1.50 weight is about 2900lbs dry, Prop is a 17 ss. I dont know if Raul the guy that built the engine adjusted the valves or not. dont think it is the carb becau it worked fine last year.

CAGE RATTLER · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

An improperly propped boat will make any engine run like a dog.

I would start there.

I put a 2010 496 mag in my boat last season. Replaced a 350 mag and the new engine seemed to have less power than the 350 till i started demo'ing props and got it dialed in. Now she jumps out of the hole and is almost 15 mph quicker on the top end. Also went from aluminum to a stainless prop.

jrturbo · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

I dont think it is a prop they told me a the marine shop that a 17 is what most people use here in utah..

Don S · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

You should be talking to Rapido first, not us.

180shabah · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

From the DIY sticky at the top of this forum

List of possible causes of low WOT (Wide Open Throttle) rpm.

In no particular order

Engine Won't Reach Operating RPM. Check

1. Fuel condition. Type and Octane possibly old fuel
2. Propeller pitch or diameter, damaged blades
3. Restricted fuel pickup tube or anti siphon valve Fuel System Test
4. Crankcase oil volume, high oil level can cause aerated oil and lifter collapse
5. Marine growth on hull and outdrive
6. Wrong gear ratio in outdrive
7. Restricted carburetor air intake (clogged flame arrestor)
8. Restricted exhaust system (broken exhaust shutters/flappers) in engine transom shield or drive
9. Poor cylinder compression Compression Test
10. Carburetor defective, or wrong type.
11. Fuel pump pressure and vacuum
12. Boat overloaded, improperly loaded, or improperly trimmed.
13. Engine Overheating
14. Engine timing and ignition system operation
15. Remote control cables and linkage for proper travel to open throttle plates fully.

You need to let us know which ones you have eliminated, and we can continue from there...

krisnowicki · Jul 24, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

sounds like a fuel system problem. And if the boat wouldn't reach more than 3000 rpms last year then it wasn't working fine then. I would go through the list above. Did you do a compression check on the engine?

If so then at 8 deg btdc you have spark and compression at the right time which would leave fuel....

Fuel+Spark+Gas= good times

John_S · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

Do the basic tests to make sure your replacement engine is in decent shape:

- Adj lifters, warm method (assuming V8)
- Check for intake/carb leaks
- Check and record compression
- Monitor engine vacuum
- Check plug condition regularly
- Adj idle mixture and idle speed, set-up choke.
- Verify ignition adv is working. (should have 25 or more degrees BTDC at 3Krpms)
- If it seems starved for fuel, go through fuel system check from tank to carb.

Make sure you have a marine carb, ignition, starter, fuel pump, and carb/flame arrestor, given you believe the prior engine was a truck engine. They might have swapped parts, but then again, might not of.

45Auto · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

jrturbo post #1 said:
Got new motor in from rapido took it out and it will not plane or get past 3000 rpm

jrturbo post #4 said:
got it last year not knowing an thing about boats and got it home found out someone pu a truck engine in it most likly out of a wrecking yard took it out 3 time woud not get over 3500 rpm and then it spun a bearing

jrturbo post #6 said:
dont think it is the carb becau it worked fine last year.

Jrturbo, there is so much missing and conflicting info in this story that the best thing you could do is take it to a real mechanic and let them fix it for you before you destroy another $2000 engine.

it just was n old truck engine with the wrong cam

You keep saying that the truck motor had the wrong cam, but you have no idea where it even came from. Hard to imagine you pulling the cam out and verifying it. Truck cam and boat cam specs are so close to identical that you can't tell them apart. Do you have any idea what the specs were on the cam you think was "wrong"?

Sounds to me like the cam is something you're trying to blame your problems on because the old engine didn't run right (just like your new one doesn't run right). The real problem is just waiting to cost you another engine.

Doernuth · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

jrturbo said:
I dont think it is a prop they told me a the marine shop that a 17 is what most people use here in utah..

Can anyone tell me whats wrong with this statement? Props are specifict to boat/engine/drive combos and what others are using in the same geographic area is completely irrelevent.

FIND A NEW MARINE SHOP NOW!!!!!!

Decreasing pitch of prop will increase RPM's Increasing pitch will decrease RPM's.

Raystownboater · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

jrturbo said:
got it home found out someone pu a truck engine in it most likly out of a wrecking yard took it out 3 time woud not get over 3500 rpm and then it spun a bearing, so know I got this engine from rapido and put it in and it is lacking power. it feel like it has too much wight but I know that is not it.

If you got the engine from Rapido, you again have a truck motor in your boat. They build their motors from truck blocks. I have 5.0 from Raul in mine and didnt have any issues with the motor. My issues (for those who have followed my questions) came from components from the old motor. It sounds like you may be having the same issues with your original components. If you had the same problem before swapping engines, I would concentrate on parts you swapped into the new engine. Distributor, coil, carb, fuel pump, etc.

jrturbo · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

It is not the same problem the old engine would it up to 35 mph and plane not not 8 mph and push water?

Raystownboater · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

jrturbo said:
took it out 3 time woud not get over 3500 rpm and then it spun a bearing, so know I got this engine from rapido and put it in and it is lacking power.

I misunderstood what you wrote. Your post made it seem like you are having the same issue with the new motor. I would definitely get Raul on the phone.

jrturbo · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

ok talk to Raul he told me it sounds like it is running lean and to spray car cleaner around the intake to see if it changes sound and tighten the carb so I did now it is starting right up no problem idles great. He said to re torq the intake also. The valve will need to be adjusted after a tank of gas.

jrturbo · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

Do you think I have do any damage this motor? I hope I did not do any damage to it and this was the problem.

180shabah · Jul 25, 2011

Re: Got new motor in from rapido took it out and it will not plane or get past 3000 r

How much time did you spend running it lean????

Got new motor in from rapido took it out and it will not plane or get past 3000 rpm

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