1994 88 SPL losing power at planing speeds

[wwerdell]

I took my boat out a couple of times this weekend after changing the thermostats and the water pump. The first day we spent the whole tme in a minumum wake zone and it ran great for the full 5 hours. Today I took it out and brought the boat up to planing speed. It ran fine for about 15 minutes then I couldn't get back up over 2000 rpms. It ran fine at lower RPMs (1400 to 2000) but it wouldn't give me any more than 2200 RPMS even at full throttle. We fished for about 3 hours then I tried to bring it up to plane on the way home. It lasted about 5 minutes and did the same thing.

The engine wasn't overheating (I could touch both sides for about 3 - 4 seconds without burning myself) and I didn't really have a problem starting it or running it at lower speeds. When I brought it home and put the earmuffs on to clean it I could rev the motor up to 4000+ rpms without any problem.

Any suggestions as to where to start looking for the problem?

 

[Daviet]

Re: 1994 88 SPL losing power at planing speeds

Sounds like a fuel delivery problem. If you can cure the problem by pumping the primer bulb, it may be time to overhaul or replace the fuel pump.
Clogged high speed jets can also cause an engine not to run at high speed, lack of fuel to the engine.

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

The bulb stays pretty firm and pumping it really made no difference in the way it ran. I also checked the fuel filter to make sure no debris got through the fuel line clogging it up.

Would the jets be a problem that occurs intermitantly? I am not really comfortable working on carbs so if it seems like the problem is going to be located there then I will probably have to take it in and have it looked at.

 

[Daviet]

Re: 1994 88 SPL losing power at planing speeds

http://www.ishopmarine.com/ishop/jsp/AsplIsmCcatViewBase.jsp?&lvlCode=5&pCode=C0164179&path=BRP~A0000008~M0009237~M0009372~M0009373~C0164179&isFromCMS=false&hideAdd2CartButton=&isStandAlone=&is4CmsShop=&reqln=Unknown&reqem=Unknown&reqph=Unknown&reqFor=29&req4Browse=1&docId=&docName=&isForSupStore=false&cCatFilter=&eCatSupFldr=The jets are pretty easy to check, you will the proper fitting screw driver to remove them. Look at # 13.

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

The jets do look like they are easy to pull out. I was looking at the float bowl to see how easy it would be to get in there and noticed there is a very small crack where the set screw sits. There is a small drip of gas coming off that screw on one side so it appears as if I will need to replace the whole float bowl assembly.

 

[keefallan]

Re: 1994 88 SPL losing power at planing speeds

Redoing the carbs on a crossflow motor really is easy. I was a little nervous myself. Just make sure you have a manual(just in case). There are only a few things you need to pay attention to. 1)chase the idle circuits with a piece of soft metal wire. That guarantees that the passge is clear. All 3 sets of jets(per carb) unthread. Clean em in carb cleaner. Pay attention to the #'s on them and which ones came out of what holes. The float level needs to be parallel to the base of the carb when inverted upside down. The rebuild kits come with everything you need and many parts you don't.

As far as the float bowl goes, it's gonna run you 80 bucks for one! I checked for myself because I needed 2 of them because mine were warped. Fortunately, I found a set of used carbs on ebay and got 3 carbs for the price of 1 float bowl. Good luck.......

 

[emdsapmgr]

Re: 1994 88 SPL losing power at planing speeds

Do you have plastic or aluminum float bowls on those carbs?

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

It looks like they are black plastic.

I found the whole float bowl assembly here on-line for 83.00. I am assuming that will come with all the parts necessary to replace the bowl. Will I need to replace any ohther gaskets as I pull the carb off?

I do have a Seloc manual for Envinrude motors - I might have to give it a try myself.

 

[emdsapmgr]

Re: 1994 88 SPL losing power at planing speeds

Those black plastic fuel bowls can be a problem. They will all warp over time. Depending on where they warp, you can fuel leakage into the cowling, or even air leaks (lean running conditions) in the carbs. Probably best to replace them. OMC used to make a complete replacement kit. If you order just the original carb bowl part number, you will get an aluminum bowl instead, as a replacement. You will find one of the jets will not fit the new bowl, (I think it is the intermediate jet) so will have to replace them. Also, the carb bowl drain screws may be different on the newer aluminum bowls, so you may have to replace them also. You may be able to reuse the rubber gasket between the bowl and the carb body.

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

I have taken the carb off the engine and removed the float bowl which was definitely cracked on both sides. I picked up a used aluminum bowl at a local marine store and was told it should work. All the holes match up, the bowls fits up against the Carb and the high speed jets seem to fit in the new bowl alright but the design is slightly different.
The plastic bowl I took off has part number 435733 and the aluminum replacement part has a part number D-1 317020. Can anyone tell me if these parts are interchangeble?

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

Looking at the aluminum float a little closer, it does not seem to have the removable intermediate orifices that the plastic float has. Also the high speed jets screw in smoothly but one doe not go in as far as the other and I didn't look at the plastic one to see if this is normal.

 

[emdsapmgr]

Re: 1994 88 SPL losing power at planing speeds

317020 does not appear to be a valid consumer part number. It may be a casting number used internally by Bombardier and may be sold under another part number. There are a number of different carb bowls configurations for different carbs. You need the one that matches your engine.

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

That very well could be the casting number instead of a part number. There was already a high speed jet in one side which is why the new one I was trying to put in did not go in all the way.

The mechanic that sold the bowl to me said it should work and that the intermediate jets are there. They are just not removeable like the ones on mine. The only other option is to purchase a new one for 80 bucks but he suggested putting this one one first to try it out. It appears to match otherwise so I am going to give it a try.

I'll let you know how it turns out.

 

[wwerdell]

Re: 1994 88 SPL losing power at planing speeds

The lower carb float bowl had a crack in it as well so I ended up replacing both float bowls. The lower carb also had a lot of black gunk in it so I ended cleaning and rebuilding both carbs as well. It wasn't really as hard as I thought it would be.

The engine runs a little better now but I am still losing power at higher RPM's. If I try to run the engine steadily at about 2500 RPMs or more it will run fine for a couple of minutes and then drop down to about 15 rpms. The primer bulb becomes limp and if I don't pump it the engine will surge back up to 2500 and then back down repeatedly. If I give it more throttle it will run fine until I level off again.

I have seen some posts that suggest it might be a fuel pump problem or that it could have to do with the stator. Any suggestions on what to test next and how to test it would be appreciated.

 

[BIGG MIKE]

Re: 1994 88 SPL losing power at planing speeds

I have taken the carb off the engine and removed the float bowl which was definitely cracked on both sides. I picked up a used aluminum bowl at a local marine store and was told it should work. All the holes match up, the bowls fits up against the Carb and the high speed jets seem to fit in the new bowl alright but the design is slightly different.
The plastic bowl I took off has part number 435733 and the aluminum replacement part has a part number D-1 317020. Can anyone tell me if these parts are interchangeble?

i have a 1994 88 spl johnson and my float bowl where the plug goes in is cracked need to know if there is a part# for a replacement plastic float bowl for this engine, i'll go ahead and replace all of them so i need 4 of them or there direct replacements. Thanks need help

 

[emdsapmgr]

Re: 1994 88 SPL losing power at planing speeds

Wwerdell, it's possible that your fuel pump is going bad. A weak fuel pump will not deliver enough fuel to run a long time at WOT rpm's. It may for a short time, then return to idle while the pump fills the carb bowls back with fuel, when it will take off again for a short time. This cycle will repeat, as the carbs draw the fuel down and the pump struggles to refill the bowls. To test this theory: try constantly priming the fuel hose bulb. If the engine runs fine at WOT as long as you constantly prime the fuel hose bulb, you've got a fuel delivery problem-including a possible weak fuel pump. You need to be careful with replacing the jets. The mid jets in the bowls are not the same size from an original plastic bowl, to the ones required in a replacement aluminum bowl. The orfice needs to be the same (flow) size, but the thread diameters are different and they look different. That's the only issue with replacing the plastic bowls with aluminum-the mid jet size. You need to consult a factory service manual which has a chart of the various jet sizes/screw sizes and order the correct replacements.

 

[racerone]

Re: 1994 88 SPL losing power at planing speeds

--------Fairly old post I am sure the original poster has this all sorted out by now !----I am guessing that some folks stumble onto this site and immediately attach to an old post instead of starting fresh for their motor.

 

[emdsapmgr]

Re: 1994 88 SPL losing power at planing speeds

Good catch, racerone. I was still answering the original post, and not recently added one.