evinrude slow moving

[schafdog]

I have a 90 horse evinrude on a 19 foot glasply impulse. Motor runs great. compression is good in all cylinders carbs rebuilt new wires plgs and fuel line. she runs great but takes a few minutes to get up to full speed and then only 3800 rpms. Is it to big of prop it has a 17 on it or is it bad gas or is this all i get for this size of boat???????? Please help with any advice to get the full potential out of this motor. Thank You Schafdog

 

[JB]

Re: evinrude slow moving

Prop topic.

 

[Dhadley]

Re: evinrude slow moving

A 17 on a V4 on a 19' boat sounds really close. I would assume we have a tach or motor issue. If it were strictly a prop issue you'd have to lose about 10" of pitch to gain the 2000 rpm. That would put you in the range of a 7" pitch prop. Since they dont make one we need to look elsewhere.<br /><br />When you advance the throttle does the timer base move all the way to the stop? Are the carb butterflies open to horizontal?

 

[rickdb1boat]

Re: evinrude slow moving

What kind of speed are you getting right now? That will tell more about the Tach. being off...

 

[mjbrueck]

Re: evinrude slow moving

I'm not sure which style the Impulse is, but if it's one of the hardtops, a 17 pitch prop is way too much. I'd think that even for their center consoles, you'd probably be closer to a 15 pitch prop with 90 hp (don't know the weight, but they seem to be a pretty beefy boat, 2000+ pounds?)<br /><br />Also, you can't apply the 200rpms/inch guide for a large rpm change - the relationship between engine speed and prop pitch is not linear. I wouldn't use that guide for more than a 1 or 2" pitch change.

 

[schafdog]

Re: evinrude slow moving

I just bought this thing from a dealer and the boat would not even get up on plane. He had all this work done to find out a reed valve was bad they replaced it. Now she gets up on plane but takes forever would never pull a skier up. I have no idea about the timing but the carbs are open at full throttle. the boat is a open bow not a hard top but a very heavy boat. The motor seems to want to go like hell but something is holding it back. thanks for any help. Oh and whenthe motor is turned off the tach sticks at arouns 1800 rpms. i do not know the speed approximately 25 to 32 at 3800 rpm

 

[Texasmark]

Re: evinrude slow moving

It's important that you give us accurate information to help you resolve your issue.<br /><br />90 hp on a heavily loaded 19' boat is not a lot of hp and yes it could take you time to plane out even if your are setup properly. If your WOT rpm's are really 3800 you are in deep doo do and if corrected, would really do a number on your slow plane out. You need some drastic changes.....so get the numbers accurate, give them to the forum and sit back and watch the help pour in.<br /><br />My 2c,<br /><br />Mark

 

[schafdog]

Re: evinrude slow moving

well what more do ya need its a 90 horse evinrude on a 19 foot glasply. revs up to over 5000 rpms in neutral. under load wot is only 3800 rpms. this is what i am asking about why am i only at 3800 when there is so much more rpms left to go thanks for your help

 

[walleyehed]

Re: evinrude slow moving

schafdog, first, NEVER (for your protection) run an outboard over 2000rpm in neutral...you're lucky it came down from 5000...you can shut the key off and it will continue to run away until something breaks...with no-load conditions, it doesn't even need sparkplugs beyond a given RPM..you are very lucky.<br />I'm at 3600ft above sea-level...here it would take a 13 pitch on that size of boat with a PROPERLY running 90...sea-level or close, a 15 pitch i think would be the most you could get by with, but that's not going to get the R's where they should be. Gut instinct tells me an unhealthy engine, and I have to wonder what happened to the reeds??

 

[astro1]

Re: evinrude slow moving

I have been working with a 17' bass boat with a 90 evinrude (and jack plate) so far I am only getting 5300 rpm and 33mph with a 15" pitch prop at 2000' above sea level.

 

[Texasmark]

Re: evinrude slow moving

I'm at about 800 ft with a 17 ft tin lizzie, Merc 90 hp 2.3 gear ratio running 6250 rpms at 49 mph. Ballistic 13 1/8 x 21 and need to go to a 24 but won't.<br /><br />No brag just fact. Black just runs better ......ya ya ye ya ya Kenny......couldn't help the gouge. Big laugh.<br /><br />Mark

 

[schafdog]

Re: evinrude slow moving

thanks for all the advice gentlemen i guess i will start looking for a bigger motor...... anybody know where to get a 120 to 140 in the seattle area????? Thanks again!!!!! Schafdog