Power Loss on 88 special

[txjimmy]

I have a 1996 88 special that began to idle rough on the last trip. I examined it and found a cracked plastic piece assosicated with the manual choke which was causing air to be sucked in the system. I replaced that with a new part and it began to idle just fine. After a warm up, I took off and the engine ran just fine for about a 100 yards. At that point, it fell back to about 4000 rpms and would not power up past that. I spun the boat around and made it cavitate and the rpms reved up to nearly 6000. When I straighted it back up and let the prop catch to "put it back under a load", it again fell back to 4000 rpms. It idles fine and is not missing, but it will not get full rpm under a load. I did check the fire at the plugs and its firing good, there is no miss in the engine and there is no noticeable fuel leak. I checked the filter at the pump and it was clear, the tank vent is clear of obstruction as well and there is no indication of a vacuum being pulled on the system. The pump bulb gets hard when its pumped up and there are no signs of any leaks. Any suggestions ?

 

[JB]

Re: Power Loss on 88 special

Howdy, Jimmy.<br /><br />You may have a throttle plate not opening all the way, ignition not advancing all the way, or a weak fuel pump.<br /><br />Most likely, you are running on 3 cylinders. It is critical that you find and correct the trouble without running the engine any more than required to troubleshoot.<br /><br />Smooth "sounding" idle and free revving without load can be delivered by that engine that is on 2 cylinders, and headed for major damage.<br /><br />Since you have confirmed spark on all 4, it is likely that one or two carb throats are not delivering fuel or not delivering it above idle.<br /><br />Squirt some fuel premix into each carb throat at idle. If the engine picks up, that carb requires rebuild. If you get no effect, or if the engine stumbles on all four, try the same thing at open throttle under load.<br /><br />Let us know what you find.<br /><br />Good luck.

 

[ob]

Re: Power Loss on 88 special

Also under load ,try repeatedly bumping the primer button on the keyswitch and see if the engine picks up.Had the engine sat out of use for a spell before the last outing?

 

[txjimmy]

Re: Power Loss on 88 special

Not really. I use it pretty often and I had just put fresh gas and oil in it. I did idle it and pull the plug wires off one at a time and seemed to that all were firing as removing each did make a significant difference in the idle of the engine. I called Portland Marine and the tech there suggested a fuel pump. I will try the above posted troubleshooting ideas first, then I guess I will try to tackle the fuel pump. By the way, I grew up in Corpus.....James

 

[ob]

Re: Power Loss on 88 special

Wow,Don't see too many homeboys on here James.Welcome aboard.If you suspect a failing fuel pump,You should be able to get some engine reaction by pumping the primer bulb when the engine won't progress.This will help you minimize the culprit.Could even be something as simple as a faulty primer bulb or sticking anti-syphon valve on the fuel tank fitting.Make sure that the crankcase pulse hose that actuates the pump diapragm is connected securely and has no leaks.Good luck and post back with the results of your findings.<br /><br />BTW ,My mom lives in Portland,and I lived there from 5th grade thru High school.

 

[txjimmy]

Re: Power Loss on 88 special

Holly cow, I moved to Portland in 5th grade. My mother still lives there too. That is where my boat is. I am a G-P graduate. Small world...James