1993 spl 88

i just recently got this motor running out on the lake on my 1989 raycraft v174. the motor starts off great, has alot of torque and gets to the max speed no problem. after running for about an hour the motor bogs down to about 10mph. even with the throttle the boat does not push like it should. i notice it starts doing this when i am making a turn either way. it slowly starts losing horse power even with the throttle at max. i slow it down to an idle and put into nuetral. i've tried maybe cleaning out by reving it in nuetral for a while to give the motor a break and clean out the engine. but even after the boat won't get up past 10 mph. has anyone had this problem? i pulled the cover of the motor and it shows that the throttle is completely floored but there is no extra response from the engine. My guess would be that this has to do with the carbureator. any help would be appreciated.

Re: 1993 spl 88

You may be losing spark to one or more plugs. Weak ignition components tend to fail when the engine heats up to normal operating temps. When it won't run check for spark at all 4 plugs.