1968 9.5 looses RPM

[Viper2872]

I just bought this earlier this spring and am having some troubles with it. Probably why the guy was selling it in the first place. It will get up to speed but only stay there for at most 30 seconds. Then the RPM cuts down to idle and just about dies. If I hold the hose up to about the tiller handle, it seems to be ok. I know it has the old style fuel filter on it and the screen/gasket should be replaced but I can't find anywhere that would carry just those parts. Also, the low speed knob has been broken off and the linkage inside is completely missing. Everything else seems to be just fine.

 

[freddyray21]

Re: 1968 9.5 looses RPM

if holding hose up keeps it running I would look to the fuel pump. Pump sounds like it is weak and not keeping the float bowl full when at wot

 

[Rick.]

Re: 1968 9.5 looses RPM

Try pumping your bulb and see if it will stay running at full speed. Your tank is venting properly? To my way of thinking, you would have to hold the tank higher, not just the hose. Best of luck. Rick.

 

[crxess]

Re: 1968 9.5 looses RPM

Also check your hose connection. Raising the hose is changing pressure on it. May be it is not fully engaging. I bought a brand new tank and hose and had this problem.

If ok, check fuel flow to pump. Pull the hose going to the pump. Place a rag around it. give the ball a squeeze. If ok, the pump may be failing.

 

[billy4hp]

Re: 1968 9.5 looses RPM

I just bought this earlier this spring and am having some troubles with it. Probably why the guy was selling it in the first place. It will get up to speed but only stay there for at most 30 seconds. Then the RPM cuts down to idle and just about dies. If I hold the hose up to about the tiller handle, it seems to be ok. I know it has the old style fuel filter on it and the screen/gasket should be replaced but I can't find anywhere that would carry just those parts. Also, the low speed knob has been broken off and the linkage inside is completely missing. Everything else seems to be just fine.

Sounds like a fuel pump problem, after you determine that and you search for a pump you will find that the original 9.5 fuel pump sells for over $80.00 and there is no direct aftermarket equiv. pump. If you search this forum most folks use the 4hp to 15hp later model pump which bolts right up but requires some rerouting of the fuel lines and it sells for under $50.00 or so I believe...

Good luck,

Billy

 

[Viper2872]

Re: 1968 9.5 looses RPM

Thanks for the replies. I had kinda figured it would be the pump and now I'll just have to order one. I was already planning on going with the newer style because I really didn't like the bend in the fuel lines that I have now. I will keep you posted on what happens.

 

[Viper2872]

Re: 1968 9.5 looses RPM

Ok...I'm trying to do some research on a replacement pump and not finding much. I'm wondering if a Sierra 18-7350 will work. I noticed that other people on this forum have said that they are using it on their 9.5. I found that the 388833 is the replacement pump for the 9822D and that the Sierra 18-7350 is the optional pump for that. Is my research correct?

Phil

 

[Viper2872]

Re: 1968 9.5 Running Rough

Re: 1968 9.5 Running Rough

So I talked to the Local Marine store and at first they said I should be able to rebuild the pump and they had the gaskets to do that in stock. I stopped there and explained the problem to the Service Tech and he suggested a Fuel System Cleaner instead. Also to try new fuel. So I dumped the old fuel and re-mixed the new fuel with the fuel system cleaner as well. Now I'm having issues getting it even started. I took it out to a lake and just could not get it going. Finally, I broke the pull rope. After replacing that, I tried again yesterday to get it going. I had it running for a little while but it was very uneven and would quit. I was trying to adjust the fuel Mixture shaft (since I don't have a knob or linkage). However that didn't seem to do anything. The last time, it fired ran for about 2 seconds and then cut out. I tried for another 45 minutes to get it going again. I pulled the fuel line off the carb and there was pressure there. I also pulled the carb apart and found there was fuel in the bowl and nothing looked out of the ordinary or worn out. I ordered the Seloc Service manual for it yesterday and am waiting for that to come.

I am out of ideas and getting frustrated with this. The guy I bought it from said that it had new points, coil, plugs and wires last fall. The mechanic also did a tune up on it so it should be good to go.

Does anyone have any ideas of what I could do?

 

[ezeke]

Re: 1968 9.5 looses RPM

First, the fuel pump that is most commonly used is the OEM model. with the aftermarket Sierra Pump # 18-7350 being very popular.

You can rebuild the small square pump with a kit, but it can be frustrating. It is simplified by using the instructions shown at this site: http://www.sschapterpsa.com/ramblings/Rebuilding_fuelpump.htm

Setting the lean/rich needle is critical, so follow Mr. Joe Reeve's instructions carefully: http://forums.iboats.com/showthread.php?t=167352

The fuel that is in the float bowl gets pulled, not pushed, from the bowl through the carburetor, so if your high speed jet is clogged, the engine won't run. It is located behind and in line with the drain plug on the float bowl where it picks up all the junk from your fuel system.

If you want the instructions on replacing the rope, send me a PM with a email and I will send them along to you. Otherwise, use a rope on the flywheel.

 

[Viper2872]

Re: 1968 9.5 looses RPM

First, the fuel pump that is most commonly used is the OEM model. with the aftermarket Sierra Pump # 18-7350 being very popular.

You can rebuild the small square pump with a kit, but it can be frustrating. It is simplified by using the instructions shown at this site: http://www.sschapterpsa.com/ramblings/Rebuilding_fuelpump.htm

Setting the lean/rich needle is critical, so follow Mr. Joe Reeve's instructions carefully: http://forums.iboats.com/showthread.php?t=167352

The fuel that is in the float bowl gets pulled, not pushed, from the bowl through the carburetor, so if your high speed jet is clogged, the engine won't run. It is located behind and in line with the drain plug on the float bowl where it picks up all the junk from your fuel system.

If you want the instructions on replacing the rope, send me a PM with a email and I will send them along to you. Otherwise, use a rope on the flywheel.

Thanks Ezeke. I have the OEM Fuel pump but like I said it seems to be working fine.

The info on the carb is great...however, I can't even get the motor to run. When it was running, idle was fine. It would cut down to idle at WOT after 15-45 seconds.

The mixture knob I am talking about is actually on the outside of the motor and says low speed and high speed. It is supposed to be linked to a shaft that goes into the carb. The link is missing but I can still turn the shaft. This is what I think is out of alignment.

As for the rope, I already replaced it. I may be doing it again as the rope is wearing with as many times I've pulled it. I think the gromet it comes through is a little rough and tearing the rope fibers.

 

[ezeke]

Re: 1968 9.5 looses RPM

There is only one adjustment on the 9.5 carburetor and that is the lean rich knob which adjusts the fuel to air mixture on the low speed orifice. Turn it out counter clockwise from gently seated 1-1/2 turns as a starting position and follow Mr. Reeves instruction to complete the adjustment.

Operating RPM is controlled by turning the tiller handle.

Check compression and spark if the motor will not fire.

You will always need to use full choke when the 9.5 is cold in order to enrich the fuel/air mix; leave it on until the engine fires.

 

[Viper2872]

Re: 1968 9.5 looses RPM

Ok. So I know its been awhile since I have posted. I've had quite a busy summer but I have done some work on it. I used the new gas, replaced the Fuel pump, readjusted the carb and cleaned the carb out. When I took the carb apart, it was spotless inside. I have it running but not well.

I can run it on idle fairly consistently and can even idle it down to shift it into gear. However, thats about it for normal. Once I get it in gear, I goes just fine for about 3 seconds and then starts to die. I pull out the choke and can keep it running but it REALLY doesn't want to. It seems like the engine is starving but I have the carb opened up really far. The Seloc's manual I got said start at 1.5 turns out from lightly seated. I would estimate that I have it at 15 turns but I really have no idea. Its really out there but that's the way I need it in order for it to idle smooth.

I'm not sure what the next step is. I think I'm going to fill the other gas tank up with just the mixed gas and give that a try. I don't know if there is an air leak somewhere that would make it run lean or if the Fuel System Cleaner might have an effect on it. Does anyone have any more ideas of what to try?

Thanks for the info.

 

[Andre]

Re: 1968 9.5 looses RPM

To me it sounds like you need to check you coils/points under the flywheel. If they are originals you might be getting a weak spark, enough to idle ok but not enough to burn the gas off the plugs when throttled. Check the plugs and see how well they are burning - do you see that they appear a bt wet?

If you do change the coils make sure you review the guide on installing them so they are positioned properly and not going to extend too far out and potentially hit the flywheel.

Andre

 

[Viper2872]

Re: 1968 9.5 looses RPM

Thanks Andre! I checked the Plugs and they looked dry. They guy I originally bought it from said that he had a mechanic go over it in the fall. I believe the points, plugs and wires are all new and the entire engine had been gone over. I don't have a flywheel puller to pull that off. Is there some other way to do that so I could check the points?

 

[Andre]

Re: 1968 9.5 looses RPM

ok-fuel pump is probably the issue then for sure. I'd suspect water in the tank could have been another possibility but lifting the hose solves your problem them it's a good place to look.

I would lso make sure your gas line and connectors is in good condition too.

 

[ezeke]

Re: 1968 9.5 looses RPM

The fuel pump can only lift so far, but if it is not working, elevate the tank above the engine and let gravity do the job so that you can see if the engine is running ok.

The fuel pump gets its "pulse" from the engine, so make sure that the gasket between the fuel pump and the engine is in place and airtight.

 

[old sailer]

Re: 1968 9.5 looses RPM

You are having to screw the idle adjust out 15 turns because you have a air leak causing it to want more fuel. screw the idle adjust all the way out and check the packing it's probobly bad. also tighten the packing nut firm.

 

[Viper2872]

Re: 1968 9.5 looses RPM

Thanks Old Sailor! I found the air leak. The hose had a bad fitting on the side of the tank. After I replaced the hose, readjusted the needle valve, it is running about 75% better. However, it is still cutting out after about 30 seconds at WOT. Almost like it is flooding the engine or starving it of air. I and set the Needle valve without the cover on because I don't have a linkage or a knob for the outside adjustment. It was running fine. Then I put it on the boat and took it out. It wouldn't start with the cover on at first. After I pulled the cover off, it started on the second pull and ran fine. When I put the cover on, the RPM dropped a little but bounced back. I'm thinking that if I were to drill a couple of small holes in the side of the cover near the carb intake, it would help it breath a little better.

 

[Viper2872]

Re: 1968 9.5 looses RPM

I haven't drilled the holes yet because I am wondering if I could screw up the mixture with it. Does anyone have any more advice as to what I could do? Would drilling the holes be a good/bad idea?

 

[sbump52]

Re: 1968 9.5 looses RPM

I was just about at the point of drillings holes also on my 64 9.5. I found that the nut that screws into the carb around the needle was loose. Tightened that and set the needle correctly and it cleared everything up. I also had replaced my fuel pump and rebuilt the carb. I had to take my carb back off and apart because I missed the high speed jet behind the drain plug on the bowl. I blew it out and made sure it was totally clear and it made a big difference. Might just be a little crude in that jet.