1992 88HP - not reaching WOT

[rjlatherow]

I took out my new(old) boat for the first time yesterday after some mild work (broken plug wire, new plugs, some carb cleaner). Tach is currently broken (that or it's hitting 8000 when its off.)<br /><br />She starts and runs smooth and lovely, but doesn't seem to reach max throttle when the throttle fully extended. From my layman point of view, she's about 50%. I have about 30 degrees of travel from the time I engage it in gear and the throttle increases. Is this normal? <br /><br />I plan on looking at the linkage, but there is precious little on adjusting this in my OMC manual. <br /><br />Or could it be something else?<br /><br />Thanks!<br />-rj

 

[Silvertip]

Re: 1992 88HP - not reaching WOT

My experience with OMC throttles is like yours -- way to much movement before carbs see any action. That said, move the throttle lever full forward. Then check the port side of the carbs and note the position of the pins in the end of the throttle plate shafts. They should point straight up. If they are short of vertical a link & sync operation is required as the throttle plates are not opening all the way. Link & sync is done with the cable disconnected. Cable adjustment is only done after the link & sync and its only purpose is to get the length right. Link & sync is far to lengthy to outline here so you need a good manual to accomplish that. The process synchronizes throttle pickup, throttle opening and ignition timing.

 

[OBJ]

Re: 1992 88HP - not reaching WOT

Let me add to Upinsmokes advice, I see from your other thread your 88 is mounted on a toon. Check your cable length and make sure they are not to long. The routing should be direct as possible with a 2.5 > 3ft loop into the engine.

 

[rjlatherow]

Re: 1992 88HP - not reaching WOT

Manual in hand, I just went out to check the alignment of the pins then set to WOT. Yikes!! they are both vertical!<br /><br />So my slop isn't the problem, but now I'm confused. I have not done anything to the carbs yet, so that may still be the problem. Rebuild??<br /><br />-rj

 

[OBJ]

Re: 1992 88HP - not reaching WOT

Couple things come to mind RJ.....<br /><br />We need to find out what rpm it's turning at WOT. How long is the toon and what is the prop pitch. To much pitch on the prop could be dragging the rpms down and lugging the engine. I've noticed that folks who own toons are apt to put high pitch props on thinking this will push the toon better and faster. Most times they just lug the engine and lose performance.<br /><br />If you don't know when the carbs were last overhauled, it would be a good idea to do that. Also check compression and engine temp to make sure the engine is reaching correct temp when running. Also, check the spark to each cylinder.

 

[Silvertip]

Re: 1992 88HP - not reaching WOT

And make sure all cylinders are contributing to the cause.

 

[rjlatherow]

Re: 1992 88HP - not reaching WOT

Wish I had a clue about the prop - just got the boat . Is there a way to figure it out? 20 foot Toon-<br /><br />I'm going to try and wake up the tach later on, which should give me more info.

 

[OBJ]

Re: 1992 88HP - not reaching WOT

The diameter and pitch are stamped on a lot of props. It'll look something like.....10X9...just grabbing numbers.<br /><br />It could also be on the prop hub.....remove the prop nut and washer. Should be stamped there.<br /><br />Yes....good idea....wakey wake the tach....

 

[rickdb1boat]

Re: 1992 88HP - not reaching WOT

Also, make sure the timing plate is moving to full advance at full throttle... On that size toon, with that motor, you should be running right at a 14"Diameter X 13"Pitch prop and hitting 5800-6000 Rpms wide open, with a light load....