bogging down

[munsterrr]

hello everyone! my friend just recently purchased a 1994 boston whaler Rage jet boat and he is already having an issue. hopefully you will have an answer....

if we put it at full throttle everything is fine for about 15 seconds then it starts bogging down. its not how many RPMS we are at(tops at 5050RPMS) even as low as 4000 it bogs down. i cant explain what it is but even at various speeds it starts bogging down and it causes us not to be able to get on the plain.

 

[Don S]

Re: bogging down

What engine?

 

[munsterrr]

Re: bogging down

its a 115 4 cylinder. thats all i know

 

[Don S]

Re: bogging down

its a 115 4 cylinder. thats all i know

Well, first of all Welcome to iboats.
Next you will need to find out EXACTLY what motor you have. Year, MAKE, model, serial numbers, all that good identifiying information. You can't fix anything if you don't even know what it is.

From that you need to determine the proper forum. This forum is for Inboard/Outdrive boats. My guess is you have an OUTBOARD motor of some make, possibly a sport jet by Mercury. It is NOT an I/O, it's an outboard motor on a jet pump mounted inside a boat. Actually it sounds more like an outboard jet.

A couple of pictures couldn't hurt to help ID your motor.

 

[munsterrr]

Re: bogging down

i will have them tomorrow sometime. thanks for your help

 

[munsterrr]

Re: bogging down

1994 OMC Two-cycle, 4 cylinder 115hp.

 

[Don S]

Re: bogging down

1994 OMC Two-cycle, 4 cylinder 115hp.

Moving to Johnson & Evinrude Outboards forum.

 

[tashasdaddy]

Re: bogging down

start with the basics, there is a troubleshooting procedure to follow. compression on all 4 with all the plugs out. needs to be above 100psi, and the numbers need to be within 10% of each other. spark with a spark tester ($10 auto parts store) must jump at least 1/2 inch bright blue spark. Record these #s for future use with the motor.

if these are all good, then we look at the fuel system. i' betting 99% on dirty high speed jets. but could also be weak fuel pump. air leak in fuel line. clogged or closed vent on fuel tank. is the primer bulb, collapsing (sucked flat)? this should keep you busy today.

remember with it being a Jet, the output is not the same as a 115 propped motor. it is more like a 75 hp motor, due to the jet drive.

 

[munsterrr]

Re: bogging down

haha thanks for the reply and the move to the correct place.

the primer bulb is not collapsed or sucked in.