Tidal Fish Forum banner

1 - 11 of 11 Posts

·
Registered
Joined
·
7,588 Posts
Discussion Starter · #1 ·
1989 Yamaha 200hp carbed two-stroke.

Idles OK, and runs and performs great at top end. Hasn't lost anything in top end RPM's or speed.

Here's what's happening - motor lugs, or labors, when accelerating slowly from a standing start, more so as rpm's begin to rise and approach about 1800-2000 rpm. Smooths out after about 2400 rpm and up, then runs like a charm.

It all began at the end of last season, and continued this season. Did the usual fogging and fuel treatment last year, and usual springtime maintenance; new plugs, spray tune, water/fuel separator, inline filter, etc, hoping for a minor fix due to a possible minor problem. No such luck.

Though repair manual points to other problems, it doesn't exactly capture this specific problem in its troubleshooting tables. What's your best guess for what's causing this? Thanks.
 

·
Registered
Joined
·
6,854 Posts
Try running some carb cleaner in the fuel. I use B-12 from Chemtrol in all of my engines. If a dirty jet isn't the problem you may want to check the ignition/timing.
 

·
Registered
Joined
·
5 Posts
BigWill,

I have the same problem on my '97 Yammie. For me the problems start around 3000 rpm and smooths out around 3800. Like you said, runs fine at slow speed or wide open. Please post what you did to fix the problem when you get it running right.

Good Luck!!!
 

·
Registered
Joined
·
888 Posts
Hmmmm...

If the problem had always been there I would suggest going to a prop with less pitch, or putting fins on your lower unit.

It's pretty much gotta be fuel, spark, or compression!

David
 

·
Registered
Joined
·
7,588 Posts
Discussion Starter · #6 ·
Yep, that's the suspicion going in. Probably overdue for a compression check, timing, synch and carb adjust. If that's all it takes to fix it, I'll be happy. I've done my part to "take care of" the innards all these years. Hopefully that all pays off with minor repairs now.
 

·
Registered
Joined
·
2 Posts
David C,

I wouldn't have fins as close to my boat as the trash bin. His problem he says started last fall so most likely the total tune up and thorough diagnosis will discover the problem. If you want to get up on plane quicker or control your boats Port/stbd. attitude then invest in trim tabs. Of course that's my opinion.
 

·
Registered
Joined
·
7,588 Posts
Discussion Starter · #9 ·
Thanks for the well wishes.

Parts for carb rebuilds just came in. But no guarantee that's the problem yet. Compression stats seemed equal enough. Should have a test run done early this week.

Hope this can help you with your diags when it's all over also!
 

·
Registered
Joined
·
7,588 Posts
Discussion Starter · #10 ·
Carbs were removed, cleaned, and rebuilt, and a cam roller, which had flat-spotted over the years, was replaced. Boat ran fine on test run this morning.

Gotta say there was no guarantee this would fix my problem going in. Glad it did.

SD - my carbs hadn't been off this motor since I bought it new in '89, and were only synch'ed maybe two or three times since new. Mechanic said they looked very clean when he got into them, but because of age, this thorough cleaning and rebuild was probably due. We're both glad it put the problem to rest.

Good luck with yours, and hope your fix goes as well as mine did.
 

·
Registered
Joined
·
5 Posts
Great to hear you're back in the saddle. Thanks again for sharing. Obviously there is no guarantee that mine has the same problem but it's nice to know where to start.
 
1 - 11 of 11 Posts
Top