97 50HP SPL Bogs down at WOT

[Fischerman]

Needs a bit of help. My 97 2cyc. 50 Hp Evinrude SPL starts great, idles just fine and runs well below 1500 rpm, but when going to WOT, it tries to spool up and then bogs down and stays under 2000 rpm. Problem is only under a "load" condition. <br /><br />I've rebuilt the carbs, replaced fuel filter, checked compression, checked gas line for leaks, replaced gas line and bulb and disconnected the slow switch lead without solving the problem. <br /><br />Any ideas or help will be deeply appreciated.<br />Thanks<br />Carl

 

[Silvertip]

Re: 97 50HP SPL Bogs down at WOT

When the engine begins to bog, squeeze the primer bulb a couple of times. If the engine picks up, its time for a fuel pump rebuild or installation of a new one. Go with a new one as its very little more money and you are sure it works when finished.

 

[Fischerman]

Re: 97 50HP SPL Bogs down at WOT

Thanks for the reply. <br /><br />Tried that as soon as the problem appeared. It had no effect. Also, I removed the cowling and could see the fuel filter and it had plenty of gas without squeezing the bulb which kind of eliminated the fuel pump as the culprit. When in neutral, I can manually (using the carb linkage) bring the rpm up to WOT rpm momentarily. All of this tends to make me wonder if it is a power pac related problem???<br />Again thanks, for the idea.

 

[fireman57]

Re: 97 50HP SPL Bogs down at WOT

Take a timing light and a friend with you and see if you are losing spark to a cylinder when this happens.

 

[Fischerman]

Re: 97 50HP SPL Bogs down at WOT

Fireman, thanks. I'll do exactly that. Appreciate the help.<br />C

 

[Silvertip]

Re: 97 50HP SPL Bogs down at WOT

Even a bad running engine with no load on it will wind up until it comes apart so thats not a valid test, especially for a fuel pump. It may be the SLOW circuit is active. This circuit goes active for oil related or overheating problems and limits engine RPM to 2000 - 2500 RPM. Does your warning horn chirp when you first turn the key on? Test the overheat sensor by grounding the overheat sensor wire with the key on. Alarm should sound. An overheat situation can be caused by worn water pump impeller, stuck thermostat, clogged cooling passages or leaky head gasket to name just a couple of issues. The pack is certainly a possible cause of the problem but be sure to eliminate everything else before replacing it. If you do have a dropped spark problem, swap coils to see if the problem follows the swap. Could be a weak coil at higher rpm.

 

[Fischerman]

Re: 97 50HP SPL Bogs down at WOT

Upinsmoke,<br />Thanks for the help. I disconnected the tan "slow" lead and it had no effect still would bog down. The warning horn does chirp when the ign. is turned on. So I bit the bullet and bought and installed a new pack. <br /><br />No help what so ever, but while testing the CDI installation on my lake, I found that by pushing <br />the choke switch in and holding it there, the boat took off like a scalded cat and sit comfortably at 5500. Release the choke and right down to 1700 rpm's. Am I looking at an over lean carb settings? Thanks for any thoughts on this frustrating problem.<br />C

 

[Walker]

Re: 97 50HP SPL Bogs down at WOT

I think what you are looking at is carbs that aren't as clean as you think they are.

 

[RandyJ]

Re: 97 50HP SPL Bogs down at WOT

Check for intake leak or possible reed valve problem. I recently had the same issue with a PWC. It ran great with about 1/2 choke. One day I pulled the reed block and found a gasket between the reeds and reed block had blown out (probably because of backfire). When I corrected this problem it ran absolutely the best it ever has.

 

[Fischerman]

Re: 97 50HP SPL Bogs down at WOT

Walker, thanks for the help. Carbs were just rebuilt by our local Marina ace. It's posible he screwed up setting the floats, I'll pull the carbs and check them and the reed valves that Randy suggested. <br /><br />Randy, thank you too. Really appreciate you guys taking the time to assist. I'll check the reed valves as that is one of the few items I haven't checked.<br /><br />Thanks guys......<br />C

 

[cvergen]

Re: 97 50HP SPL Bogs down at WOT

Whats a reed? Charlie, what was the final outcome. I just posted a similar problem but after another 1/2 hour found this thread on page 17.<br /><br />Thanks

 

[BoatBuoy]

Re: 97 50HP SPL Bogs down at WOT

What you've described is exactly how mine acted when I got water in the carb. I drained the float bowl and it ran perfect.