high rpms problem

[ForPetesSakeII]

Got my 1988 90hp hooked up to a regular pulse pump #439558 i believe... It runs fine up to about half throttle and idles great however will not plane unless i push the key in and choke it. once it gets on plane it will stay up for a little while but still seems to be lugging. Also when its idling or at low rps the choke bogs it down like it should... changed filters, pump, lines. wondering if the timing is messed up but seems like a fuel delivery problem to me. also the carbs were rebuild beginning of this season.

Thanks for any help!!

 

[Bosunsmate]

dont rebuild just check your high speed jets

 

[emdsapmgr]

You may have the wrong fuel pump. There are two types of pumps that will work on that engine. The 88 model from your year uses a two port pump, with the pump mounting face to face on the block, with a gasket0-through which the pump diaphragm gets it's pulse signals. That pump is # 438556. If you opt to use an earlier 3-legged pump which has a port for the existing VRO pulse hose, that pump is # 438559.

 

[ForPetesSakeII]

My mistake the fuel pump is #438559. I connected the vro pulse hose to the pulse port on that pump. looks like I will be taking carbs off again to check high speed jets. Are there any other kinds of adjustments I may be over looking? Just want to be sure before I take the carbs off again. Thanks

 

[Bosunsmate]

Not really, you can check your timing base is rotating to its full advanced stop when you push the throttle to wot.
Make sure you blow compressed air or carb cleaner through both high speed jets on both bottom sides of the carb, ive done those on another motor while the carbs are still on so i dont think you should need to take the carbs off. Just get one of those small tube on the carb cleaners lid and blkast through there making sure that the fluid can be heard bubbling out elsewhere, just checking the jet isnt enough as often the blockage is up stream in the passages

 

[emdsapmgr]

Sure it's got good spark? Weak ignition components tend to fail once the engine warms up to normal operating temps. Once it's fully warmed up-recheck for spark. The cyl drop test would be appropriate.

 

[ForPetesSakeII]

just checked my manual and high speed jets should be simple to get to and clean. also will check the timing base and spark later today thanks guys