shudders while driving full throttle. dog gears or electrical?

[foxy510]

i have evinrude 100 v4 and when im going half throttle its fine but when i open her up after about 10 seconds it will shudder almost like i hit something then fine for awhile then sometimes i have to throttle right down to go again? replaced prop and stuff already , buddy said it would be electrical because if it was gears it would do it all the time?

 

[boobie]

Sounds like an ignition miss. Put a timing light on it, look into the light for black spots when it happens and that will confirm an ignition miss.

 

[foxy510]

will do first thing in spring thanx hoping not dog gears... mabey pack?

 

[boobie]

Maybe ????

 

[F_R]

Banging "like you hit something" is the classic description of worn clutch dog. But I don't get the "throttle down before it will go again" part. What happens if you don't throttle down? BTW, what year is this motor?

 

[glust]

If it bangs like you hit something it sounds like the clutch dog is slipping. As it slips the contact surface of the gear and the clutch dog will get rounded off. Your problem will get worse and worse until the banging is pretty constant. Make sure gear engagement and shift rod height are correct. To rebuild the lower unit with new forward, reverse, and clutch dog can cost in the hundreds and that's if you do the work yourself. Don't ask me how I know... I also would not mess around with used clutch dogs...again, ask me how I know... Good luck with your project

 

[racerone]

Could be a totally different problem if it is a 1966 / 67 / 68 model V-4----Motor model # should be posted.

 

[emdsapmgr]

Could be a weak fuel pump. Can't provide enough fuel to run it constantly at WOT.

 

[oldboat1]

If permanent tanks, might draw off a sample and check for contamination or water. Draw from the bottom of the tank, and put a sample in a glass jar overnight to see what settles. Water will show up at the bottom of the jar.