1988 90hp VRO bogging down and will eventually run

[nhellbaum]

New to the site but have read some great things so far...

I just bought a 1988 90hp that ran great on the hose. On the water, however, when put into gear, the motor would bog down and die repeatedly. After several go rounds of this, it would finally rev up, take off and run great.

Pretty new to the world of outboards and was wondering where to start to fix this issue.

 

[racerone]

They all sound good on a hose to an untrained ear.------The motor will sound good to you running on 3 of 4 cylinders !-------My advice on these motors is always the same procedure.----Start with a compression test .--Then test for strong spark on each lead.----Spark must jump a gap of 3/8" or more.--------Try running without the cover on and see if that gives you better results.---It could be something as simple as a plug lead shorting to a cowling latch.

 

[nhellbaum]

Ok thanks! I just find it strange how well the motor runs when it finally decides to get going. If it NEVER got going, a fuel, spark, compression, etc problem would make sense.
I'm sure a good carb cleaning/rebuild wouldn't hurt either...

 

[racerone]

Trouble shooting is the process I use and recommend;--Guessing does not work.---If you can clean the carburetors yourself it may do the trick for low $$$ spent.

 

[nhellbaum]

I took the boat back out and did one simple thing. Changed the prop! I had bough and installed a nicer used prop that was a 21 pitch that i knew would fit on my engine. The one that came on the boat was a big beat up 13 pitch. Swapping back the 13" eliminated the bogging down issues and the motor ran great the whole time. I guess I didn't know switching pitch and blade size would have such a dramatic effect. I guess I will just buy a nice new 13 or 15

 

[racerone]

Sometimes owners switch to a smaller pitch prop to allow the motor to reach top RPM again.---This compensates for a motor that is not putting out the proper power.---The pitch of the prop is adjusted according to the boat that it is on .---The bigger the boat / load the smaller the pitch needs to be.----My recomendation is to do a compression test on your motor.!