Low RPMs

[KyJim]

I have a 1990 Evinrude 200 XP. It starts very well and has a decent hole shot but will only get about 4200-4300 RPMs on top end. The compressions on all cylinders is about 85 and all else seems fine. I have adjusted the motor position up and down on the jack plate with no help. The motor is on a 1990 DC HydraSport and has a 26 pitch Evinrude 4 blade prop. I have been told that the statar on this engine has a low starting output and high output for running. Any advise?

 

[Sherman]

Re: Low RPMs

Borrow a prop with 24 pitch and give it a try. Better hole shot and higher rpm at top end.

 

[CharlieB]

Re: Low RPMs

How long have you owned this motor?

Is this a recent problem or long standing problem?

Check spark QUALITY using and adjustable spark gap tester set to 1/4 inch, you should have a strong blue arc with a crisp 'snap'. Less can limit WOT RPM.

If it passes the spark test then at WOT try squeezing the primer bulb and notice if any improvement, next try momentarily pressing the enrichener/choke and notice if any improvement.

You are attempting to determine if you have any possible fuel restriction limiting power at WOT.

If NO positiive improvement with these tests then try a lower pitch prop, just remember that if the # of blades should remain the same, a 24 pitch 3 blade is a LOT less prop than a 26 pitch 4 blade, which is a lot of prop even for a 200 unless you have a very light boat.

 

[KyJim]

Re: Low RPMs

I have not owned the boat long. It was having this problem when I purchased. I have had the spark checked and told it is ok. However, someone else told me about the low-high spark and the high spark was probably low. Others have told me this engine does not have a low-high spark. I have a friend with the same boat, engine and prop and his boat turns about 5600RPMs on top end. The boat is a heavy boat. When I raised the engine on the jack plate it gets real squirrelly and does not increase the RPMs that much. The boat is not getting enough RPMs to get the boat on pad and keep it there. I was even told to lower the engine more so the boat could get more lift when trimmed out thus raising the RPMs. I am hoping to have some ideas before spring so I can try them out. I realize a smaller pitch prop will turn more RPMs but will it provide enough lift?

 

[Dhadley]

Re: Low RPMs

Tell whoever said the "hi-spark" was "low" to hold on to a plug wire while you spin it over. That should settle that debate.

A 26 may be a bit much for a 19' boat - or maybe not. Which 26" prop? What exact boat? Are you sure the motor is running as it should be? Lots of questions...where are you located?

 

[bktheking]

Re: Low RPMs

Tell whoever said the "hi-spark" was "low" to hold on to a plug wire while you spin it over. That should settle that debate.

LOL and post a vid on youtube for us while doing the test.

 

[kenmyfam]

Re: Low RPMs

I was even told to lower the engine more so the boat could get more

Lower motor = more drag !!!
Seems strange advice to me.
Just my thoughts though.

 

[Dhadley]

Re: Low RPMs

I kinda understand what they may have been talking about. With some props you may get the motor high enough that you can't get much positive trim before it vents. The motor may have to come down so more trim can be applied to get more bow lift. Not exactly how we like to achieve bow lift but I can see how it might have to work that way with some props.

We have to do the same thing with some boats like Hydrostrams. The boats have so much natural lift that you can have the plate 1/2 to 3/4 the way up at mid speed. As you go faster the hull flifts so much it'll actually pull the prop up out of the water. The plate actually comes down to keep the prop in the water. My Vegas XT was like that. Sorta doubtful this boat has that much natural lift though.

 

[junior1113]

Re: Low RPMs

i have a 93 20' hydrasport cc with 93 200 evinrude (in aviator pic). running a 17" pitch 4 blade turbo utlima 4(great lift). 48 mph @ 5900 rpm. thinkin you need to be more like in the 19-21" pitch range to achieve correct wot rpms 5500-6000. supprised that prop even got up on plane. people think the more pitch the faster the boat will go and this is why engines they blow engines. it will die very soon if it is driven like that. get it proped to 5800-6000 and it will last and run correctly. great boat great motor